## Samacheer Kalvi 9th Maths Guide Chapter 8 Statistics Ex 8.1

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## Tamilnadu Samacheer Kalvi 9th Maths Solutions Chapter 8 Statistics Ex 8.1

Question 1.
In a week, temperature of a certain place is measured during winter are as follows 26°C, 24°C, 28°C, 31°C, 30°C, 26°C, 24°C. Find the mean temperature of the week.
Solution:
Mean temperature of the week

= 27°C
Mean temperature of the week 27° C

Question 2.
The mean weight of 4 members of a family is 60 kg. Three of them have the weight 56 kg, 68 kg and 72 kg respectively. Find the weight of the fourth member.
Solution:
Weight of 4 members = 4 × 60 kg
= 240 kg
Weight of three members = 56 kg + 68 kg + 72 kg
= 196 kg
Weight of the fourth member = 240 kg – 196 kg
= 44 kg

Median Calculator is used to compute and display the median of a list of given values or a set of data.

Question 3.
In a class test in mathematics, 10 students scored 75 marks, 12 students scored 60 marks, 8 students scored 40 marks and 3 students scored 30 marks. Find the mean of their score.
Solution:
Total marks of 10 students = 10 × 75 = 750
Total marks of 12 students = 12 × 60 = 720
Total marks of 8 students = 8 × 40 = 320
Total marks of 3 students = 3 × 30 = 90
Total marks of (10 + 12 + 8 + 3) 33 students
= 750 + 720 + 320 + 90
= 1880
Mean of marks = $$\frac{1880}{33}$$
= 56.97 (or) 57 approximately
Aliter:
Total number of students = 10+12 + 8 + 3
= 33
Mean of their marks

= 56.97 (or) 57 approximately

Question 4.
In a research laboratory scientists treated 6 mice with lung cancer using natural medicine. Ten days later, they measured the volume of the tumor in each mouse and given the results in the table.

find the mean.
Solution:

$$\bar { x }$$ = $$\frac{Σfx}{Σf}$$
= $$\frac{2966}{21}$$
= 141.238
= 141.24
The Arithmetic mean = 141.24 mm³

Question 5.
If the mean of the following data is 20.2, then find the value of p.

Solution:

$$\bar { x }$$ = $$\frac{Σfx}{Σf}$$
20.2 = $$\frac{610+20p}{30+p}$$
610 + 20 p = 20.2 (30 + p)
610 + 20 p = 606 + 20.2 p
610 – 606 = 20.2 p – 20 p
4 = 0.2 p
p = $$\frac{4}{0.2}$$
= $$\frac{4×10}{2}$$
= 20
The value of p = 20

Question 6.
In the class, weight of students is measured for the class records. Calculate mean weight of the class students using direct method.

Solution:

Arithmetic mean $$\bar { x }$$ = $$\frac{Σfx}{Σf}$$
= $$\frac{2010}{50}$$
= 40.2
Arithmetic mean = 40.2

Question 7.
Calculate the mean of the following distribution using Assumed Mean Method.

Solution:
Assumed Mean (A) = 25

Arithmetic mean ($$\bar { x }$$) = A+$$\frac{Σfd}{Σf}$$
= 25 + $$\frac{270}{63}$$
= 25 + 4. 29
Assumed Mean = 29.29

Question 8.
Find the Arithmetic Mean of the following data using Step Deviation Method:

Solution:
Assumed Mean (A) = 32

Arithmetic mean = A+$$\frac{Σfd}{Σf}$$ × c
= 32 + ($$\frac{-77.5}{105}$$×4)
= 32 – 2.95
= 29.05
Arithmetic mean = 29.05

## Samacheer Kalvi 9th Social Science Guide Book Back Answers Solutions

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## Samacheer Kalvi 9th Maths Guide Chapter 3 Algebra Ex 3.15

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## Tamilnadu Samacheer Kalvi 9th Maths Solutions Chapter 3 Algebra Ex 3.15

Multiple Choice Questions.

Question 1.
If x3 + 6x2 + kx + 6 is exactly divisible by x + 2, then k = 2
(a) 6
(b) -7
(c) -8
(d) 11
Solution:
(d) 11
Hint:
p(x) = x3 + 6x2 + kx + 6
Given p(-2) = 0
(-2)3 + 6(-2)2 + k(-2) + 6 = 0
-8 + 24 – 2k + 6 = 0
22 – 2k = 0
k = $$\frac{22}{2}$$
= 11

Question 2.
The root of the polynomial equation 2x + 3 = 0 is…….
(a) $$\frac{1}{3}$$
(b) –$$\frac{1}{3}$$
(c) –$$\frac{3}{2}$$
(d) –$$\frac{2}{3}$$
Solution:
(c) –$$\frac{3}{2}$$
Hint:
2x + 3 = 0
2x = – 3 ⇒ x = –$$\frac{3}{2}$$

Online Polynomial Root Calculator. This online tool calculates the roots of a polynomial. I use this tool to calculate the roots to plot Bode diagrams.

Question 3.
The type of the polynomial 4 – 3x3 is ……..
(a) constant polynomial
(b) linear polynomial
(d) cubic polynomial
Solution:
(d) cubic polynomial

Question 4.
If x51 + 51 is divided by x + 1, then the remainder is …….
(a) 0
(b) 1
(c) 49
(d) 50
Solution:
(d) 50
Hint:
p(x) = x51 + 51
p(-1)= (-1)51 + 51
= -1 + 51
= 50

Question 5.
The zero of the polynomial 2x + 5 is ……..
(a) $$\frac{5}{2}$$
(b) –$$\frac{5}{2}$$
(c) $$\frac{2}{5}$$
(d) –$$\frac{2}{5}$$
Solution:
(b) –$$\frac{5}{2}$$
Hint:
2x + 5 = 0 ⇒ 2x = -5 ⇒ x = –$$\frac{5}{2}$$

Question 6.
The sum of the polynomials p(x) = x3 – x2 – 2, q(x) = x2 – 3x + 1
(a) x3 – 3x – 1
(b) x3 + 2x2 – 1
(c) x3 – 2x2 – 3x
(d) x3 – 2x2 + 3x – 1
Solution:
(a) x3 – 3x – 1
Hint:
p(x) + q(x) = (x3 – x2 – 2) + (x2 – 3x + 1) = x3 – x2 – 2 + x² – 3x + 1
= x³ – 3x – 1

Question 7.
Degree of the polynomial (y³ – 2) (y³ + 1) is
(a) 9
(b) 2
(c) 3
(d) 6
Solution:
(d) 6
(y³ – 2) (y³ + 1) = y6 + y³ – 2y³ – 2
= y6 – y³ – 2

Question 8.
Let the polynomials be
(A) -13q5 + 4q² + 12q
(B) (x² + 4)(x² + 9)
(C) 4q8 – q6 + q²
(D) –$$\frac{5}{7}$$ y12 + y³ + y5.
Then ascending order of their degree is
(a) A, B, D, C
(b) A, B, C, D
(c) B, C, D, A
(d) B, A, C, D
Solution:
(d) B, A, C, D

Question 9.
If p(a) = 0 then (x – a) is a …….. of p(x)
(a) divisor
(b) quotient
(c) remainder
(d) factor
Solution:
(d) factor

Question 10.
Zeros of (2 – 3x) is ……..
(a) 3
(b) 2
(c) $$\frac{2}{3}$$
(d) $$\frac{3}{2}$$
Solution:
(c) $$\frac{2}{3}$$

Question 11.
Which of the following has x -1 as a factor?
(a) 2x – 1
(b) 3x – 3
(c) 4x – 3
(d) 3x – 4
Solution:
(b) 3x – 3

Question 12.
If x – 3 is a factor of p(x), then the remainder is ……..
(a) 3
(b) -3
(c) p(3)
(d) p(-3)
Solution:
(c) p(3)

Question 13.
(x +y)(x² – xy + y²) is equal to ……..
(a) (x + y)³
(b) (x – y)³
(c) x³ + y³
(d) x³ – y³
Solution:
(c) x³ + y³

Question 14.
(a + b – c)² is equal to ……..
(a) (a – b + c)²
(b) (-a – b + c)²
(c) (a + b + c)²
(d) (a – b – c)²
Solution:
(b) (-a – b + c)²
Hint:
(a + b – c)² = a² + b² + c² + 2ab – 2bc – 2ac
(- a – b + c)² = a² + b² + c² + 2ab – 2bc – 2ac
(OR)
(- a – b + c)² = (-1)² (a + b + c)² (taking – 1 as common)
= (a + b – c)²

Question 15.
In an expression ax² + bx + c the sum and product of the factors respectively ……..
(a) a, bc
(b) b, ac
(c) ac, b
(d) bc, a
Solution:
(b) b, ac

Question 16.
If (x + 5) and (x – 3) are the factors of ax² + bx + c, then values of a, b and c are ………
(a) 1, 2, 3
(b) 1, 2, 15
(c) 1, 2, -15
(d) 1, -2, 15
Solution:
(c) 1, 2, -15
Hint:
(x + 5) (x – 3) = x² + (5 – 3) x + (5) (-3)
= x² + 2x – 15
compare with ax² + bx + c
a = 1, b = 2 and c = -15

Question 17.
Cubic polynomial may have maximum of ……… linear factors.
(a) 1
(b) 2
(c) 3
(d) 4
Solution:
(c) 3

Question 18.
Degree of the constant polynomial is ……..
(a) 3
(b) 2
(c) 1
(d) 0
Solution:
(d) 0

Question 19.
Find the value of m from the equation 2x + 3y = m. If its one solution is x = 2 and y = -2.
(a) 2
(b) -2
(c) 10
(d) 0
Solution:
(b) – 2
Hint:
The equation is 2x + 3y = m
Substitute x – 2 and y = -2 we get
2(2) + 3(-2) = m ⇒ 4 – 6 = m ⇒ -2 = m

Question 20.
Which of the following is a linear equation?
(a) x + $$\frac{1}{2}$$ = 2
(b) x (x – 1) = 2
(c) 3x + 5 = $$\frac{2}{3}$$
(d) x³ – x = 5
Solution:
(c) 3x + 5 = $$\frac{2}{3}$$

Question 21.
Which of the following is a solution of the equation 2x – y = 6?
(a) (2, 4)
(b) (4, 2)
(c) (3, -1)
(d) (0, 6)
Solution:
(b) (4, 2)
Hint:
2x – y = 6
Substitute x – 4 and y = 2 we get
2(4) – 2 = 6 ⇒ 8 – 2 = 6 ⇒ 6 = 6
∴ (4, 2) is the solution

Question 22.
If (2, 3) is a solution of linear equation 2x + 3y = k then, the value of k is ……..
(a) 12
(b) 6
(c) 0
(d) 13
Solution:
(d) 13
Hint:
The equation is 2x + 3y = k
Substitute x = 2 and y = 3 we get,
2(2) + 3(3) = k ⇒ 4 + 9 = k ⇒ 13 = k

Question 23.
Which condition does not satisfy the linear equation ax + by + c = 0 ……..
(a) a ≠ 0, b = 0
(b) a = 0, b ≠ 0
(c) a = 0, b = 0, c ≠ 0
(d) a ≠ 0, b ≠ 0
Solution:
(c) a = 0, b = 0, c ≠ 0

Question 24.
Which of the following is not a linear equation in two variable?
(a) ax + by + c = 0
(b) 0x + 0y + c = 0
(c) 0x + by + c = 0
(d) ax + 0y + c = 0
Solution:
(b) 0x + 0y + c = 0
Hint:
0x + 0y + c = 0
0 + 0 + c = 0 ⇒ c = 0
There is no variable.
∴ It is not a linear equation

Question 25.
The value of k for which the pair of linear equations 4x + 6y – 1 = 0 and 2x + ky – 1 = 0 represents parallel lines is ……..
(a) k = 3
(b) k = 2
(c) k = 4
(d) k = -3
Solution:
(a) k = 3
Hint:
Slope of 4x + 6y – 1 = 0 is
6y = -4x + 1 ⇒ y = $$\frac{-4}{6}$$ x + $$\frac{1}{6}$$
Slope = $$\frac{-4}{6}$$ = $$\frac{-2}{3}$$
Slope of 2x + ky – 7 = 0
ky = -2x + 7
y = $$\frac{-2}{k}$$x + $$\frac{7}{k}$$
Slope of a line = $$\frac{-2}{k}$$
Since the lines are parallel
$$\frac{-2}{3}$$ = $$\frac{-2}{k}$$
-2k = – 6
k = $$\frac{6}{2}$$
= 3

Question 26.
A pair of linear equations has no solution then the graphical representation is ……..

Solution:

Hint:
Since there is no solution the two lines are parallel. (l11m)

Question 27.
If $$\frac{a_1}{a_2}$$ ≠ $$\frac{b_1}{b_2}$$ where a1x + b1y + c1 = 0 and a2x + b2y + c2 = 0 then the given pair of linear equation has …….. solution(s).
(a) no solution
(b) two solutions
(c) unique
(d) infinite
Solution:
(c) unique
Hint:
Since it has unique solution
$$\frac{a_1}{a_2}$$ ≠ $$\frac{b_1}{b_2}$$

Question 28.
$$\frac{a_1}{a_2}$$ = $$\frac{b_1}{b_2}$$ ≠ $$\frac{c_1}{c_2}$$ where a1x + b1y + c1 = 0 and a2x + b2y + c2 = 0 then the given pair of linear equation has …….. solution(s).
(a) no solution
(b) two solutions
(c) infinite
(d) unique
Solution:
(a) no solution
Hint:
$$\frac{a_1}{a_2}$$ = $$\frac{b_1}{b_2}$$ ≠ $$\frac{c_1}{c_2}$$ the linear equation has no solution.

Question 29.
GCD of any two prime numbers is …….
(a) -1
(b) 0
(c) 1
(d) 2
Solution:
(c) 1

Question 30.
The GCD of x4 – y4 and x² – y² is ……..
(a) x4 – y4
(b) x² – y²
(c) (x + y)²
(d) (x + y)4
Solution:
(b) x² – y²
Hint:
x4 – y4 = (x²)² – (y²)²
= (x² + y²)(x² – y²)
x² – y² = (x² – y²)
G.C.D. = x² – y²

## Samacheer Kalvi 9th Science Guide Chapter 2 Motion

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## Tamilnadu Samacheer Kalvi 9th Science Solutions Chapter 2 Motion

### 9th Science Guide Motion Text Book Back Questions and Answers

Online Average Acceleration calculator can be used to calculate Acceleration,​initial and final velocity and time taken.

Question 1.
The area under velocity – time graph represents the
(a) velocity of the moving object.
(b) displacement covered by the moving object,
(c) speed of the moving object.
(d) acceleration of the moving object.
(b) displacement covered by the moving object

Question 2.
Which one of the following is most likely not a case of uniform circular motion?
(a) Motion of the Earth around the Sim.
(b) Motion of a toy train on a circular track.
(c) Motion of a racing car on a circular track.
(d) Motion of hours’ hand on the dial of the clock.
(c) Motion of a racing car on a circular track

Question 3.
Which of the following graph represents uniform motion of a moving particle?

Question 4.
The centrifugal force is
(a) a real force.
(b) the force of reaction of centripetal force.
(c) a virtual force.
(d) directed towards the centre of the circular path.
(c) a virtual force

II. Fill in the blanks :

1. Speed is a …………………….quantity whereas velocity is a …………….quantity.
Scalar, Vector

2. The slope of the distance – time graph at any point gives ………………
Speed

3. Negative acceleration is called ……………………
retardation (or) deceleration

Displacement calculator is really a nice calculator that will help you solve a lot of your problems related to displacement.

4. Area under velocity – time graph shows ……………………………….
displacement

III. State whether true or false. If false, correct the statement:

1. The motion of a city bus in a heavy traffic road is an example for uniform motion.
False.
Correct statement: The motion of a city bus in a heavy traffic road is an example for non-uniform motion.

2. Acceleration can get negative value also.
True.

3. Distance covered by a particle never becomes zero but displacement becomes zero.
True.

4. The velocity – time graph of a particle falling freely under gravity would be a straight line parallel to the x axis. .
False.
Correct statement: The velocity – time graph of aparticle moving at uniform do dry. would be straight line parallel to the x axis.

5. If the velocity – time graph of a particle is a straight line inclined to X-axis then its displacement – time graph will be a straight line.
True.

IV. Assertion and Reason Type Questions :

Mark the correct choice as:
(a) If both assertion and reason are true and reason is the correct explanation of assertion.
(b) If both assertion and reason are true but reason is not the correct explanation of assertion.
(c) If assertion is true but reason is false.
(d) If assertion is false but reason is true.

Question 1.
Assertion : The accelerated motion of an object may be due to change in magnitude of velocity or direction or both of them..
Reason : Acceleration can be produced only by change in magnitude of the velocity. It does not depend the direction.
(c) If assertion is true but reason is false.

Use Average Velocity Calculator to find the average velocity, initial velocity, and final velocity with average velocity formula (vavg=(v+u)/2).

Question 2.
Assertion : The Speedometer of a car or a motor-cycle measures its average speed.
Reason : Average velocity is equal to total displacement divided by total time taken.
(d) Assertion is false but reason is true

Question 3.
Assertion : Displacement of a body may be zero when distance travelled by it is not zero.
Reason : The displacement is the shortest distance between initial and final position.
(a) Both assertion and reason are true and reason is the correct explanation of assertion

V. Match the Following :

Question 1.
Define velocity.
Velocity is the rate of change of displacement. It. is the displacement in unit time.

Question 2.
Distinguish distance and displacement.
Table
Distance

1. The actual length of the path travelled by a moving body irrespective of the direction
2. It is a Scalar quantity

Displacement:

1. The change in position of a moving body in a particular direction
2. It is a Vector quantity

Question 3.
What do you mean by uniform-motion?
An object is said to be in uniform motion if it covers equal distances in equal intervals of time how so ever big or small these time intervals may be.

Question 4.
Compare speed and velocity.

 Speed Velocity 1. It is the rate of change of distance with respect to time It is the rate of change of displacement with respect to time 2. It is a scalar quantity having magnitude only It is a vector quantity having both magnitude and direction 3. Speed is velocity without a particular direction Velocity is speed in a particular direction 4. It is measured in ms-1 in SI system It is also measured in ms-1 in a particular direction in SI system 5. Speed in any direction would be a positive quantify, since the distance in any direction is a positive quantity. Velocity can get both positive and negative values. If velocity in one direction is assumed to be positive then the velocity in the opposite direction would be a negative quantity. Velocity can get zero value also.

Question 5.
What do you understand about negative acceleration?
If v < u, i.e. if final velocity is less than initial velocity, the velocity decreases with time and the value of acceleration is negative. It is called negative acceleration. It is also called as retardation (or) deceleration.

Question 6.
Answer: When an object is moving with a constant speed along a circular path, the change in velocity is only due to the change in direction. Hence it is accelerated motion.

Question 7.
What is meant by uniform circular motion? Give two examples of uniform circular motion.
When an object moves with constant speed along a circular path, the motion is called uniform circular motion.
Example :

• The earth moves around the sun in the uniform circular motion.
• The moon moves in uniform circular motion around the earth.

Question 1.
Derive the equations of motion by graphical method.
Equations of motion from velocity-time graph:

Graph shows the change in velocity with time of a uniformly accelerated object. The object starts from the point D in the graph with velocity u. Its velocity keeps increasing and after time t it reaches the point B on the graph.
The initial velocity of the object = u = OD = EA
The final velocity of the object = v = OC = EB
Time = t = OE = DA
Also from the graph we know that, AB = DC

1. First equation of motion :

By definition, acceleration = change in velocity / time
= (final velocity – initial velocity)/time
= (OC – OD) / OE
= DC / OE
a = DC /t
DC = AB = at
From the graph EB = EA + AB
v = u + at…………..(1)
This is first equation of motion. .

2. Second equation on of motion :
From the graph the distance covered by the object during time t is given by the area of quadrangle DOEB

s = area of the quadrangle DOEB
= area of the rectangle DOEA + area of the triangle DAB
= (AE x OE) + (1/2 × AB × DA) .
s = ut + 1/2 (at2) …………(2)
This is the second equation of motion.

3. Third equation of motion :
From the graph the distance covered by the object during time, t is given by the area of the quadrangle DOEB. Here DOEB is a trapezium. Then,
s = area of trapezium DOEB
= 1/2 × sum of length of parallel side × distance between parallel sides
= 1/2 × (OD + BE) × OE
S = 1/2 ×× (u + v) × t
since a = (v – u) /1 or t = (v – u) / a
Therefore s = 1/2 × (v + u) x (v – u) / a
2as = v2 – u2
v2 = u2 + 2 as …………….. (3)
This is the third equation of motion.

Question 2.
Explain different types of motion.
In physics, motion can be classified as below.

1. Linear motion: Motion along a straight line.

2. Circular motion: Motion along a circular path.

3. Oscillatory motion: Repetitive to and fro motion of an object at regular intervals of time. Random motion: Motion of the object which does not fall in any of the above categories.

Uniform and Non-uniform motion:

Uniform motion: Consider a car that covers 60 km in the first hour, 60 km in the second horn-, and another 60 km in the third hour, and so on. The car covers equal distance at equal intervals of time. We can say that the motion of the car is uniform. An object is said to be in uniform motion if it covers equal distances in equal intervals of time howsoever big or small these time intervals may be.

Non-uniform motion: Now, consider a bus starting from one stop. It proceeds slowly when it passes through a crowded area of the road. Suppose, it manages to travel merely 100 m in 5 minutes due to heavy traffic and is able to travel about 2 km in 5 minutes when the road is clear. Hence, the motion of the bus is non-uniform i.e. it travels unequal distances in equal intervals of time.

VIII. Exercise Problems:

Question 1.
A ball is gently dropped from a height of 20 m. If its velocity increases uniformly at the rate of 10ms-2, with what velocity will it strike the ground? After what time will it strike the ground?
Here we have
Initial velocity, u = 0
Distance, s = 20 m
Acceleration, a = 10 m/s2
Final velocity, v = ?
Time, t = ?

a) Calculation of final velocity, v
We know that, v2 = u2 + 2as
v2 = 0 + 2 × 10m/s2 × 20m
v2 = 400m2/s2
$$=\sqrt{400 m^{2} / s^{2}}$$
v = 20m/s

b) Calculation of time, t
We know that, v = u + at
20 m/s = 0 + 10m/s2 × t
t = $$\frac{20 m / s^{2}}{20 m / s}=2 s$$
∴ Ball will strike the ground at a velocity of 20 ms-1
Time taken to reach the ground = 2s.

Question 2.
An athlete completes one round of a circular track of diameter 200 m in 40 s. What will be the distance covered and the displacement at the end of 2 m and 20 s?
Here we have
Diameter = 200. m
∴ Radius = 200 m/2 = 100 m
Time of one rotation = 40 s
Time after 2m 20 s = 2 × 60 s +20 s = 140 s
Distance after 140 s = ?
Displacement after 140 s = ?
Circular track with a diameter of 200m
We know that, velocity

a) Distance after 140 s
We know that, distance = velocity × time
= Distance 15.7 rn/s × 140 s
= 2198m

b) Displacement after 2 min 20 s i.e, in 140 s
We know that, distance = velocity × time
Since, rotation in 40 s = 1
∴ Rotation in 1 s = $$\frac{1}{40}$$
∴ Rotation in 140 s = $$\frac{1}{40} \times 140=3.5$$
∴ In 3.5 rotation athlete will be just at the opposite side of the circular track,
i.e. at a distance equal to the diameter of the circular track which is equal to 200m
∴ Distance covered in 2min 20 s = 2198 m
Displacement after 2min 20 5 = 200 m.

Question 3.
A racing car has a uniform acceleration of 4ms-2. What distance it covers in 10s after the start?
Here we have
Acceleration, a = 4 m/s2.
Initial velocity u = 0
Time t = 10 s
Distance (s) covered =?
We know that, s = ut + $$\frac { 1 }{ 2 }$$ at2
s = (0 × 10s) + [$$\frac { 1 }{ 2 }$$ × 4 m/s2 × (10 s)2]
= $$\frac { 1 }{ 2 }$$ × 4 m/s2 × 100 s2
= 2 × 100 m = 200 m

Thus, racing car will cover a distance of 200 m after start in 10s with given acceleration.

Intex Activities

ACTIVITY – 1

Look around you. You can see many things: a row of houses, large trees, small plants, flying birds, running cars and many more. List the objects which remain fixed at their position and the objects which keep on changing their position.
Solution:

1. Row of houses, large trees, small plants are the examples, of immovable objects.
2. Flying birds, running cars and buses are the examples of movable objects.

Activity to be done by the students themselves

ACTIVITY – 2

Tabulate the distance covered by a bus in a heavy traffic road in equal intervals of time and do the same for a train which is not in an accelerated motion. From your table what do you understand?
The bus covers unequal distance in equal intervals of time but the train covers equal distances in equal intervals of time.
Solution:

ACTIVITY – 3

Observe the motion of a car as shown in the figure and answer the following questions:
Compare the distance covered by the car through the path ABC and AC. What do you observe? Which path gives the shortest distance to reach D from A? Is it the path ABCD or the path ACD or the path AD?

Solution:

1. Distance covered by the car through the path ABC = 4m + 3m = 7 m. and AC = 5 m. The distance covered by the car through the path ABC is large compared to AC.
2. The shortest distance to resell D from A is path AD = 3m.
3. The total distance covered by the car ABCD A = 14 m. It finally reaches to A.

ACTIVITY – 4

Take a large stone and a small eraser. Stand on the top fit a table and drop them simultaneously from the same height? What do you observe? Now, take a small eraser and a sheet of paper. Drop them simultaneously from the same height. What do you observe? This time, take two sheets of paper having same mass and crumple one of the sheets into a ball. Now, drop the sheet and the ball from the same height. What do you observe?
Solution :
Both the stone and the eraser have reached the surface of the earth almost at the same time.
The eraser reaches first and the sheet of paper reaches later.
The paper crumpled into a ball reaches ground first and plain sheet of paper reaches later, although they have equal mass. It is because of air resistance. The magnitude of air resistance despends on the area of object exposed to air. So the sheet of paper reaches later.

I. Choose the correct answer :

Question 1.
A particle is moving in a circular pattern of radius r. The displacement after half a circle would be
(a) zero
(b) πr
(c) 2r
(d) 2πr
(c) 2r

Question 2.
In which of the following cases of motions, the distance moved and the magnitude of displacement are equal?
(a) If the car is moving in the straight road.
(b) If the car is moving in a circular road.
(c) The earth is revolving around the sun.
(d) The pendulum is moving to and fro
(a) If the car is moving in the straight road

Question 3.
A body is thrown vertically upward with velocity, the greatest height h to which it will rise is
(a) u2/2g
(b) u2/g
(c) u/g
(d) u/2g
(a) u2/2g

Question 4.
If the displacement of an object is proportional to square of time, then the object moves with
(a) uniform velocity
(b) uniform acceleration
(c) increasing acceleration
(d) decreasing acceleration
(b) uniform acceleration

Question 5.
From the given v-t graph, u can be inferred that the object is
(a) in uniform motion
(b) at rest
(c) in non-uniform motion
(d) moving with uniform acceleration
(a) in uniform motion

Question 6.
The area under v-t graph represents a physical quantity which has the unit.
(a) m2
(b) m
(c) m3
(d) ms-1
(b) m

Question 7.
m/s2 is the unit of
(a) distance
(b) displacement
(c) velocity
(d) acceleration
(d) acceleration

Question 8.
The rate of change of displacement
(a) speed
(b) velocity
(c) acceleration
(d) retardation
(b) velocity

Question 9.
A scalar quantity has T
(a) magnitude only
(b) direction only
(c) both
(d) none
(a) magnitude only

Question 10.
When an object undergoes acceleration
(a) there is always an increase in its velocity
(b) there is always an increase in its speed
(c) a force always acting on it.
(d) all of the above
(c) a force always acting on it

Question 11.
A body is projected up with an initial velocity u m/s. It goes up to a height, ‘h’ metres in seconds time. Then it comes back at the point of projection. Considering negligible air resistance, which of the following statement is true?
(a) the acceleration is zero
(b) the displacement is zero
(c) the average velocity is 2hit
(d) the final velocity is 2u when body reaches projection point
(b) the displacement is zero

Question 12.
A car accelerates at 1.5m/s2in a straight road. How much is the increase in velocity in 4s.
(a) 6 m/s
(b) 4 m/s
(c) 3 m/s
(d) 2.66 m/s
(a) 6 m/s

Question 13.
The slope of the distance-time curve is steeper / greater is the
(a) velocity
(b) acceleration
(c) displacement
(d) speed
(d) speed

Question 14.
The given graph represents motion with …………….speed.

(a) uniform
(b) non-uniform
(c) constant
(d) none
(b) non-uniform

Question 15.
The relation between displacemeñt and time is given by the equation of
(a) v2 = ut + at
(b) s = ut + $$\frac { 1 }{ 2 }$$ at2
(e) c = s/t
(d) v2 = u2 + 2as
(b) s = ut + $$\frac { 1 }{ 2 }$$ at2

Question 16.
A body moves in a uniform circular motion
(a) It is moving with constant velocity
(b) its acceleration is zero
(c) the body has an acceleration y
(d) none of the above
(a) It is moving with constant velocity

Question 17.
Speed of the body in particular direction can be called
(a) acceleration
(b) displacement
(c) velocity
(d) distance
(c) velocity

Question 18.
Statement A: Uniform circular motion is a case of accelerated motion
Statement B: In third equation of motion we do not have the term time
(a) Statement B is true, A is false
(b) Statement A is true, B is false
(c) neither statement A nor B is true
(d) both are true
(d) both are true

Question 19.
Which of the following is correct about uniform circular motion
(i) direction of motion is continuously changed
(ii) direction of motion is not changed
(iii) speed and direction both remain constant
(iv) speed is constant but direction is changing
(a) ii & iii are correct
(b) i, ii & iii are correct
(c) i & iv are correct
(d) all of these
(c) i & iv are correct

Question 20.
Which of the quantities have the same SI unit?
(a) speed, velocity
(b) acceleration, time
(c) velocity, time
(d) velocity, acceleration
(a) speed, velocity

Question 21.
Rest and motion of body are
(a) non-relative
(b) not related
(c) relative
(d) none
(c) relative

Question 22.
An ant moves from one corner of a room diagonally to the opposite corner. If the dimensions of the hall are 8m x 6m, the displacement of the ant is
(a) 10m
(b) 14m
(c) 28m
(d) 2m
(a) 10m

Question 23.
The displacement covered by a second hand of radius V in a clock after one revolution is
(a) 360°
(b) 0
(c) 3r
(d) 2r
(b) 0

Question 24.
A man leaves his house at 6.30 a.m. for a morning walk and returns back at 7.30 a.m. after covering 4 km. Displacement covered by him is …………….
(a) 2 km
(b) zero
(c) 8 km
(d) 4 km
(b) zero

Question 25.
A body is said to be in non uniform motion if it travels
(a) equal distance in unequal interval of time
(b) equal distance in equal interval of time
(c) unequal distance in unequal interval of time
(d) unequal distance in equal interval of time.
(d) unequal distance in equal interval of time

Question 26.
A quantity which has both magnitude and direction is
(a) scalar
(b) distant
(c) vector
(d) moving body
(c) vector

Question 27.
A bus accelerating with 4ms-2 changes its speed from 60ms_1 to a certain value in 5s. The final speed is
(a) 40 m/s
(b) 25 ms-1
(c) 60 ms-1
(d) 30 ms-1
(a) 40 m/s

Question 28.
A quantity has a value of 16ms-2. It is the
(a) acceleration of an object
(b) velocity of an object
(c) retardation of an object
(d) speed of an object
(c) retardation of an object

Question 29.
A boy throws a ball up and catches it when the ball falls back. In which part of the motion the ball is accelerating?
(a) during downward motion
(b) when the ball comes to rest
(c) during upward motion
(d) when the boy catches the ball.
(a) during downward motion]

Question 30.
Choose the correct option.
(a) distance is a scalar, velocity is a vector, acceleration is a vector
(b) distance is a vector, velocity is a scalar, acceleration is a vector
(c) distance is a vector, velocity is a vector, acceleration is a vector
(d) distance is a scalar, velocity is a vector, acceleration is scalar
(a) distance is a scalar, velocity is a vector, acceleration is a vector

Question 31.
If a moving body comes to rest, then its acceleration is
(a) positive
(b) negative
(c) zero
(d) all of these depending upon initial velocity.
(b) negative

Question 32.
If the velocity of a body changes uniformly from u to v in time t, the sum of average velocity and acceleration is

Question 33.
Acceleration is defined as the rate of change of
(a) distance
(b) velocity
(c) speed
(d) displacement
(b) velocity

Question 34.
When an object undergoes acceleration
(a) there is always an increase in its velocity ‘
(b) there is always an increase in its speed
(c) a force always acting on it.
(d) all the above
(c) a force always acting on it

Question 35.
The equation v = u + at gives information as
(a) velocity is a function of time
(b) velocity is a function of position
(c) position is a function of time
(d) position is a function of time and velocity
(a) velocity is a function of time

Question 36.
Which of the following can determine the acceleration of a moving object.
(a) area of the velocity-time graph
(b) the slope of the velocity-time graph
(c) area of a distance-time graph
(d) the slope of a distance-time graph
(b) slope of the velocity-time graph

Question 37.
What is the slope of the body when it moves with uniform velocity?
(a) positive
(b) negative
(c) zero
(d) may be positive or negative
(c) zero]

Question 38.
If a body starts from rest, what can be said about the acceleration of the body?
(a) positively accelerated
(b) negative accelerated
(c) uniform accelerated
(d) none of the above
(a) positively accelerated

Question 39.
When a body moves uniformly along the circle then
(a) its velocity changes but speed remain the same
(b) its speed changes but velocity remains the same
(c) both speed and velocity changes
(d) both speed and velocity remains same
(a) its velocity changes but speed remains the same

Question 40.
Distance travelled by a freely falling body is proportional to
(a) mass of the body
(b) square of the acceleration due to gravity
(c) square of the time of fall
(d) time of fall
(c) square of the time of fall

Question 41.
If the displacement-time graph of a particle is parallel to the time axis, then velocity of the particle is.
(a) infinity
(b) unity
(c) equal to acceleration
(d) zero
(d) zero

Question 42.
In the velocity-time graph, AB shows that the body has

(a) uniform acceleration
(b) non-uniform retardation
(c) uniform speed
(d) initial velocity OA & is moving with uniform retardation.
(d) initial velocity OA & is moving with uniform retardation

Question 43.
The magnitude of the centripetal force is given by (F= ….)

Question 44.
A body moving with an initial velocity 5ms-1 and accelerates at 2ms -2. Its velocity after 10s is
(a) 20ms-1
(b) 25ms-1
(c) 5ms-1
(d) 22.55ms-1
(b) 25ms-1

Question 45.
In a 100m race, the winner takes 10s to reach the finishing point. The average speed of the winner is
(a) 5ms-1
b) 20ms-1
c) 40ms-1
d) 10ms-1
(d) 10ms-2

Question 46.
The area under the velocity-time graph represents
(a) the velocity of the moving object
(b) displacement covered by the moving object
(c) speed of the moving object.
(d) acceleration of the moving object
(b) displacement covered by the moving object

Question 47.
A car is being driven at a speed of 20ms-1 when brakes are applied to bring it to rest in 5 s. The deceleration produced in this case will be
(a) +4ms-2
(b) -4ms-2
(c) -0.25ms-2
(d) +0.25ms-2
(b) -4ms-2

Question 48.
Unit of acceleration is
(a) ms-1
(b) ms-2
(c) ms
(d) ms2
(b) ms-2

Question 49.
The force responsible for drying clothes in a washing machine is …………….
(a) Centripetal force
(b) Centrifugal force
(c) Gravitational force
(d) Electro static force
(b) Centrifugal force

II. Fill in the blanks:

1. If a body does not change its position, then it is said to be at …………………
rest

2. The back and forth motion of a swing is an ………………… motion.
Oscillatory

3. In uniform motion an object travels equal ………………… in ………………… interval of time.
distances, equal

4. The actual path covered by a body is called …………………
distance

5. Displacement is the ………………… distance covered by a body.
shortest

6. The motion of the bus is ………………… motion.
non-uniform

7. Rate of change of displacement is …………………
velocity

8. Speed is a ………………… quantity whereas velocity is a …………………
scalar, vector

9. If final velocity is less than initial velocity the acceleration is ………………….
negative

10. If final velocity is equal to initial velocity the value of acceleration is ………………….
zero

11. The slope of the distance-time graph becomes steeper & steeper the speed ………………….
increases

12. A straight line parallel to the x-axis in the velocity-time graph, represents the object moves in…………………
uniform velocity

13. From v-t graph ………………… can be calculated.
displacement

14. ………………… measures the instantaneous speed of the automobile.
Speedometer

15. Slope of the velocity-time graph gives…………………
acceleration

16. The value of acceleration for a body at rest is…………………
zero

17. At the highest point, when a body is thrown vertically upwards, the velocity is ………………….
zero

18. A body moves in a circular pattern the ………………… of velocity does not change but changes.
magnitude, direction

19. When a body moves in a circular pattern ………………… acceleration is directed radially towards the centre of the circle.
centripetal

20. The separation of cream from milk-hn example for the application of ………………….
centrifugal

21. Consider an object is rest at position x = 20m. Then its displacement – time graph will be straight-line ………………… to the time axis.
Parallel

III. State whether true or false. If false, correct the statement:

1. Displacement can be zero but distance never.
True.

2. Time is a vector quantity.
False.
Correct statement: Time is a scalar quantity.

3. Displacement magnitude can be greater than the distance travelled by the object.
True.

4. If the velocity of the body decreases with time the acceleration is negative and the motion is called decelerated motion.
True.

5. Acceleration is a scalar.
False.
Correct statement: Acceleration is a vector.

6. The area of the velocity-time graph gives the displacement of the body.
True.

7. Motion & rest are relative terms.
True.

8. An object can be moving with uniform speed but variable acceleration.
True.

9. Slope of the distance-time graph indicates the speed.
True.

10. It is possible to have object moving with uniform velocity but non-uniform acceleration.
True.

11. It is possible to have object moving with uniform speed but variable acceleration.
False.
Correct statement : It is possible to have object moving with uniform speed but constant acceleration.

12. The force experienced by a boy in the merry-go-round is a centripetal force.
False.
Correct statement: The force experienced by a boy in the merry-go-round is a centrifugal force.

13. The initial velocity of a freely falling object is zero as it is released from rest.
True.

IV. Assertion and Reason Type Questions :

(a) If both assertion & reason are true and the reason is the correct explanation of the assertion.
(b) If both assertion & reason are true but the reason is not correct explanation of the assertion.
(c) If the assertion is true but the reason is false.
(d) If assertion & reason both are false.
(e) If assertion is false but reason is true.

Question 1.
Assertion : A body can have acceleration even if its velocity is zero at a given instant of time.
Reason: A body is momentarily at rest when it reverses its direction of motion.
(a) Both assertion & reason are true and the reason is the correct explanation of the assertion

Question 2.
Assertion : If the displacement of the body is zero, the distance covered by it may not be zero.
Reason: Displacement is a vector & distance is a scalar quantity.
(a) Both assertion & reason are true and the reason is the correct explanation of the assertion

Question 3.
Assertion: An object can have constant speed but the variable velocity
Reason: Speed is a scalar but velocity is a vector.
(a) Both assertion & reason are true and the reason is the correct explanation of the assertion

Question 4.
Assertion: The speed of a body can be Negative.
Reason : If the body is moving in the opposite direction of positive motion, then its speed is Negative.
(d) Assertion & reason both are false

Question 5.
Assertion : The position-time graph of a uniform motion in one dimension of a body can have Negative slope
Reason : When the speed of body decreases with time then, position-time graph of the moving body has Negative slope.
(c) Assertion is true but the reason is false

Question 6.
Assertion: A positive acceleration of a body can be associated with slowing down of the body.
Reason: Acceleration is a vector.
[Answer: (b) Both assertion & reason are true but the reason is not correct explanation of the assertion]

Question 7.
Assertion :A negative acceleration of a body can be associated with speeding up of the body.
Reason: Increase in speed of a moving body is independent of its direction of motion.
(b) Both assertion & reason are true but the reason is not the correct explanation of the assertion

Question 8.
Assertion When a body is subjected to a uniform acceleration, it is always moving in a straight line.
Reason: Motion may be straight-line motion or circular motion.
(e) Assertion is false but the reason is true

Question 9.
Assertion : Position-time graph of a stationary object is a straight line parallel to time axis. ’
Reason : For a stationary object, position does not change with time.
(a) Both assertion & reason are true and the reason is the correct explanation of the assertion

Question 10.
Assertion : The slope of distance-time graph of a body moving with high speed is steeper than slope of distance-time graph of a body with low velocity.
Reason: Slope of distance-time graph = speed of the body.
(a) Both assertion & reason are true and the reason is the correct explanation of the assertion

Question 1.
What are centripetal acceleration and centripetal force?
When a body moves in a circular pattern the acceleration is directed radially towards the centre of the circle.
The force causing this acceleration is also directed towards the centre of the circle and it is called centripetal force.

Question 2.
Find the magnitude of centripetal force.
Consider an object of mass m, moving along a circular path of radius r, with a velocity v, its centripetal acceleration is given by a = v2 / r
Hence, the magnitude of centripetal force is given by,
F = mass x centripetal acceleration
F = mv2 / r

Question 3.
What is centrifugal force? Give examples.
Force acting on a body away from the centre of circular path is called centrifugal force. Thus centrifugal force is in a direction opposite to the direction of centripetal force. Its magnitude is same as that of centripetal force.
Example : Spin dryer of a washing machine, ride on a merry-go-round.

Question 4.
When an object is thrown upwards, what is true of velocity and acceleration at the highest point of motion of the object?

• Velocity becomes zero
• Acceleration remains same as g.

Question 5.
Name the two quantities, the slope of whose graph gives (i) speed (ii) acceleration.
(i) Distance – Time
(ii) Speed – Time

Question 6.
Define Average speed.
It is the total distance travelled divided by the total time taken to cover this distance.

Question 7.
What do you infer if
(i) Distance – time graph is straight line.
(ii) Velocity time graph is curved.
(iii) Displacement time is zig zag.
(i) Speed is constant.
(ii) Acceleration is not uniform.
(iii) Non uniform velocity.

Question 8.
Give the formula for each.
(i) Relation between initial, final velocity, acceleration and displacement in a uniformly accelerated straight line motion.
(ii) Relation between initial, final velocity, acceleration & time in a uniformly accelerated straight line motion.
(iii) Relation between initial velocity, acceleration, displacement and time.
(i) Relation between initial, final Velocity, acceleration & displacement
in a uniformly accelerated straight line motion. v2 = u2 + 2as
(ii) Relation between initial, final velocity, acceleration & time
in a uniformly accelerated straight line motion. v = u + at
(iii) Relation between initial velocity, acceleration, displacement and time. s = ut+ 1/2 at2

Question 9.
What is the difference between uniform acceleration and non – uniform acceleration?
Uniform Acceleration

1. It is the acceleration in which the object changes its velocity with equal intervals of time.
2. eg. The motion of a ball rolling down.

Non – Uniform Acceleration

1. It is the acceleration in which the object changes its velocity with unequal intervals of time.
2. A car travels 2 km in 1st hour, 3 km in 2nd hour and 3.5 km in 3rd horn.

Question 11.
Define Acceleration.
Acceleration is the rate of change of velocity with respect to time or it is the rate of change of velocity in unit time. It is a vector quantity. The SI unit of acceleration is

VI. Paragraph Questions :

Question 1.
Define acceleration and state its SI unit for motion along a straight line, when do we consider the acceleration to be (i) positive (ii) negative? Give an example of a body in uniform acceleration.
Answer: Acceleration is the rate of change of velocity with respect to time or it is the rate of change of velocity in unit time. It is a vector quantity. The SI unit of acceleration is ms-2
Acceleration = Change in velocity/time
= (Final velocity – initial velocity)/time
a = $$\frac{v-u}{t}$$

If v > u, then ‘a’ is positive. If final velocity is greater than initial velocity, the velocity increase with time, the value of acceleration is positive.

If v < u, then a is negative. If final velocity is less than initial velocity
Example : The motion of a freely falling body and vertically thrown up body are the examples of uniform acceleration.
The motion of ball rolling down on an inclined plane is another example.

Question 2.
Distinguish between uniform motion and non
uniform motion.

1. An object is said to be in uniform motion if it covers equkl distances in equal intervals of time.
2. example of uniform motion ‘train’

non-uniform motion.

1. If a body covers unequal distances in equal interval of time (or) equal distances in a different interval of time
2. example of non – uniform motion ‘bus’

Question 3.
Define uniform circular motion and give an example of it. Why is it called accelerated motion?
When an object is moving with a constant speed along a circular path, the change in velocity is only due to the change in direction. Hence it is accelerated motion. Example:

1. The earth moves around the sun in a uniform circular motion.
2. The moon moves in uniform circular motion around the earth.

Question 4.
When a body is said to be in (i) uniform acceleration (ii) non – uniform acceleration?
(i) A body is said to be in uniform acceleration if it travels in a straight line and its velocity increases or decreases by equal amounts in equal time intervals.
(ii) A body is said to be in non-uniform acceleration if the rate of change of its velocity is not constant i.e. differs in different time intervals.

Question 5.
What remains constant in uniform circular motion? And what changes continuously in uniform circular motion?

• Speed remains constant in a uniform circular motion.
• Velocity changes continuously in a uniform circular motion.

Problems

Question 1.
A bus speed decreases from 50 km/h to 40 km/h in 3s, find the acceleration of the bus.

Question 2.
A car starting from rest moves with uniform acceleration of 0.2 ms-2 for 3 min. Fine the (a) speed acquired (b) the distance travelled.
Initial speed (u) = 0 m/s
Acceleration (a) = 0.2 ms-2
Time taken (t) = 3 min = 3 × 60 = 180 s
Final velocity (v) = ?
Distance covered(s) = ?
v = u + at = 0 + 0.2 × 180 = 36 m/s
v = 36m/s
s = ut + 1/2 at2 = 0 + 1/2 × 0.2 × (180)2
= 0.1 × 32400 = 3240 m
s = 3240m

Question 3.
A train is travelling at a speed of 90 kmh-1. Brakes are applied so as to produce a uniform acceleration of-0.5 ms-2, find how far the train will go before it is brought to rest.
Initial velocity of train (u) = 90 km/h = $$\frac{90,000 \mathrm{~m}}{3,600 \mathrm{sec}}=25 \mathrm{~ms}^{-1}$$
Final velocity (v) = 0 ms-1
Acceleration (a) = – 0.5 ms-2
v2 = u2+ 2as
s = (v2 – u2) / 2a = (02 – 252) / -(2 × 0.5)
s = -625/-1 = 625m
s = 625m

Question 4.
In a long-distance race the athletes were expected to take four rounds of the track such that the line of finish was same as the line of start. Suppose the length of the track was 300m,

(i) What is the total distance to be covered by the athletes?
What is the total displacement of the athletes when they touch the finish line?
(iii) Is the motion of the athletes uniform or non- D .^starting point uniform?
(iv) Is the displacement & distance moved by an athlete at the end of the race equal?
(i) Total distance covered = 4 × 300 = 1200 m
(ii) Displacement = 0 [final position – initial position]
(iii) Non – uniform.
∵ the direction of motion is changing while running on the track.
(iv) Both are not equal.

Question 5.
Ram swims in a 80m long swimming pool. He covers 160m in 1 min by swimming from one end to the other and back along the same straight pattern. Find the average speed and average velocity.
Total distance = 160m
Total displacement = 0
Time taken (t) = 1 min = 60s

Question 6.
Abus from Chennai travels to Trichy passes loo km, 160 km at 10.15 am, 11.15 am respectively. Find the average speed of the bus during 10.15 – 11.15 am.
The distance coveredbetween 10.l5am& 11.15 am = 160 – 100
= 60km
The time interval = 1 h
Average speed = 60/1
= 60km/h

Question 7.
In a distance-time graph of two objects A & B, which object is moving with greater speed when both are moving?
Object B makes a longer angle with the time – axis. Its slope is greater than the slope of object A. Thus the speed of B is greater than that of A.

Question 8.
Find the distance covered by a particle during the time interval which the speed-time graph is-shown in figure.

Distance covered in the. time interval 0 to 20s is equal to the area of the triangle OAB.
Area of A OAB. $$\frac { 1 }{ 2 }$$ × base × height
$$\frac { 1 }{ 2 }$$ × 20 x 20 = 200 ms-1

Question 9.
A car moves 30 km in 30 min and the next 30 km in 40 min. Calculate the average speed for the entire journey.
Total time taken = 30 + 40 = 70 min. = $$\frac { 70 }{ 60 }$$ hour
Total distance = 30 + 30 = 60 km

Question 10.
A boy travels a distance of 3m due east and then 4m due north.
(a) How much is the total distance covered?
(b) What is the magnitude of the displacement?

(a) Total distance covered = 3 + 4 = 7m
(b) Net displacement: OB2 = OA2 + AB2
= 32 + 42
OB2 = 25m2
∴OB = 5m 0 3m
Net displacement = 5m

Question 11.
During an experiment, a signal from a spaceship reached the ground station in five seconds. What was the distance of the spaceship from the ground station? The signal
travels at the speed of light that is 3 × 108 ms-1
Time taken = 5 seconds.
Speed of signal u = 3 × 108 m/s ?
Distance = ?
Speed = Distance / Time
∴ Distance = Speed × Time
Distance = 3 × 108 × 5 = 15 × 108 m.

Question 12.
A train travelling at a speed of 90kmph. Brakes are applied so as to produce a uniform acceleration of -0.5 ms-2. Find how far the train will go before it is brought to rest?
Here we have
Initial velocity , u = 90km/h
$$=\frac{90 \times 1000 \mathrm{~m}}{60 \times 60 \mathrm{~s}}=25 \mathrm{~m} / \mathrm{s}$$
Final velocity, v = 0
Acceleration, a = -0.5m/s2
Thus, distance travelled = ?
We know that, v2 = u2 + 2as

Question 13.
The adjacent diagram shows the velocity-time graph of the body.
a) During what time interval is the motion of the body accelerated?
At 0 to 4 second

b) Find the acceleration in the time Interval mentioned in part ‘a’.
$$\mathrm{a}=\frac{v-u}{t}=\frac{30-0}{4}=7.5 \mathrm{~m} / \mathrm{s}^{2}$$

c) What is the distance travelled by the body in the time interval mentioned ¡n part ‘a’?
Answer:Distance travelled Area under the graph
= Area of the triangle = 1/2 bh
= 1/2 × 4 × 30 = 60m

Question 14.
The following graph shows the motion of a car. What do you infer from the graph along with OA and AB? What is the speed of the car along with AB and what time it reached this speed?
a) What do you infer from the graph along OÄ and AB
Graph along with OA: The car travels with uniform acceleration and uniform motion.
Graph along with AB : The car travels with constant speed and unaccelerated motion.

b) What is the speed of the car along AB?
Along AB : The speed of the car is constant.
From the graph, it seems the speed along AB is 72 km/hr.

c) What time it reached this speed
It reaches this speed after 3.2 hours, that is, 3 hours, 12 minutes.

Question 15.
From the following table, check the shape of the graph.

## Samacheer Kalvi 9th Science Guide Chapter 18 Organization of Tissues

Tamilnadu State Board New Syllabus Samacheer Kalvi 9th Science Guide Pdf Chapter 18 Organization of Tissues Text Book Back Questions and Answers, Notes.

## Samacheer Kalvi 9th Science Solutions Chapter 18 Organization of Tissues

### 9th Science Guide Organization of Tissues Text Book Back Questions and Answers

Question 1.
The tissue composed of living thin walled polyhedral cell is
(a) parenchyma
(b) pollenchyma
(c) pclerenchyma
(d) none of above
(d) none of above

Question 2.
The fibres consists of
(a) parenchyma
(b) sclerenchyma
(c) collenchyma
(d) none of above
(b) sclerenchyma

Question 3.
Companion cells are closely associated with
(a) sieve elements
(b) vessel elements
(c) trichomes
(d) guard cells
(a) sieve elements

Question 4.
Which of the following is a complex tissue?
(a) Parenchyma
(b) Collenchyma
(c) Xylem
(d) Sclerenchyma
(c) Xylem

Question 5.
Aerenchyma is found in
(a) epiphytes
(b) hydrophytes
(c) halophytes
(d) xerophytes
(b) hydrophytes

Question 6.
Smooth muscles occur in
(a) uterus
(b) artery
(c) vein
(d) all of the above
(d) all of the above

Question 7.
Nerve cell does not contains
(a) axon
(b) nerve endings
(e) tendons
(d) dendrités
(c) tendons

II. Match the following.

Question 1.

 Sclereids Chlorenchyma Chloroplast Sclerenchyma Simple tissue Collenchyma Companion cell Xylem Tracheids Phloem

 Sclereids Sclerenchyma Chloroplast Chlorenchyma Simple tissue Collenchyma Companion cell Phloem Tracheids Xylem

III Fill in the blanks :

1. ……………. tissues provide mechanical support to organs.
Compound epithelium

2. Parenchyma, Collenchyma, Sclerenchyma are ……………. type of tissue.
simple

3. ……………. and ……………… are complex issues.
Xylem, phloem

4. Epithelial cells with cilia are fóund in ……………….. of our body
trachea or windpipe

5. Lining of the small intestine is made up of …………………..
columnar epithelium

IV. State whether true or false. If false, correct the statement :

1. Epithelial tissue is protective tissue in an animal body.
True.

2. Bone and cartilage are two types of areolar connective tissue.
False.
Correct statement: Bone and cartilage are two types of supportive connective tissue.

3. Parenchyma is a simple tissue.
True.

4. Phloem is made up of tracheids.
False.
Correct statement: Phloem is made up of sieve tubes.

5. Vessels are found in collenchyma.
False.
Correct statement: Vessels are found in the xylem.

Question 1.
What are intercalary meristems? How do they differ from other meristems?
Intercalary meristem lies between the region of permanent tissues and is part of primary meristem which is detached due to formation of intermittent permanent tissues. It is found either at the base of leaf e.g. Pinus or at the base of intemodes e.g. grasses.

Question 2.
What is complex tissue? Name the various kinds of complex tissues.

• Complex tissues are made of more than one type of cells that work together as a unit.
• Complex tissues consist of parenchyma and sclerenchyma cells. However, collenchymatous cells are not present in such tissues.
• Common examples are xylem and phloem.

Question 3,.
Mention the most abundant muscular tissue found in our body. State its function.
Connective tissue is the most abundant and widely distributed tissue. It provides a structural framework and gives support to different tissues forming organs.

Question 4.
What is skeletal connective tissue? How is it helpful in the functioning of our body?
The supporting or skeletal connective tissues forms the endoskeleton of the vertebrate body. They protect various organs and help in locomotion. The supportive tissues include cartilage and bone.

Question 5.
Why should gametes be produced by meiosis during sexual reproduction?
Meiosis is important as it produces gametes i.e., male or female germ cells. During meiosis, a germ cell or gamete divides to make four new sex cells. As a result of fertilization two gamates join together to form an egg or zygote. Therefore only if gametes are produced, fertilization can take place.

Question 6.
In which stage of mitosis the chromosomes align in an equatorial plate? How?
Metaphase (meta – after) The duplicated chromosomes arrange on the equatorial plane and form the metaphase plate. Each chromosome gets attached to a spindle fibre by its centromere. The centromere of each chromosome divides into two each being associated with a chromatid.

Question 1.
What are the permanent tissues? Describe the different types of simple permanent tissues.
Permanent tissues:
Permanent tissues are those in which, growth has stopped either completely or for the time being. At times, they become meristematic partially or wholly.

Different types of simple permanent tissue :
Simple tissue: Simple tissue is homogeneous-composed of structurally and functionally similar cells. Eg : Parenchyma, collenchyma, and sclerenchyma.

Parenchyma:

• Parenchyma are simple permanent tissue composed of living cells.
• Parenchyma cells are thin-walled, oval, rounded, or polygonal in shape with well-developed spaces among them.
• In aquatic plants, parenchyma possesses intercellular air spaces and is named as aerenchyma.
• When exposed to light, parenchyma cells may develop chloroplasts and are known as chlorenchyma.

Functions:

• Parenchyma may store water in many succulent and xerophytic plants.
• It also serves the functions of storage of food reserves, absorption, buoyancy, secretion, etc

Collenchyma:

• Collenchyma is a living tissue found beneath the epidermis.
• Cells are elongated with unevenly thickened non-lignified walls. Cells have rectangular oblique or tapering ends and persistent protoplast.
• They possess thick primary non-lignified walls.
Functions: They provide mechanical support for growing organs.

Sclerenchymà:

• Scierenchyma consists of thick-walled cells which are often lignified.
• Scierenchyma cells do not possess living protoplasts at maturity. Scierenchyma cells are grouped into

(i) fibers and (ii) sclereids.

Fibres : Elongated scierenchymatous cells, usually with pointed ends. Their walls are lignified. Fibres are abundantly found in many plants. Eg. Jute.
Sclereids:

• Sclereids are widely distributed in plant body. They are usually broad, may occur in single or in groups.
• Sclereids are isodiametric, with lignified walls. Pits are prominent and seen along the walls.
• Lumen is filled with wall materials. Sclereids are also common in fruits and seeds.

Question 2.
Write about the elements of Xylem.
Xylem is a conducting tissue which conducts water, mineral nutrients upward from root to leaves. Xylem is also meant for mechanical support to the plant body. Xylem is composed of different kinds of elements. They are

1. xylem tracheids
2. xylem fibres
3. xylem vessels and
4. xylem parenchyma.

(i) Xylem tracheids: They are elongated or tube-like dead cells with hard, thick and lignified walls. Their ends are tapering, blunt or chisel-like. These cells are devoid of protoplast. They have large lumen without any content. Their function is conduction of water and providing mechanical support to the plant.

(ii) Xylem fibers: These cells are elongated, lignified and pointed at both the ends. Xylem fibres help in the conduction of water and nutrients from root to the leaf and also provide mechanical support to the plant.

(iii) Xylem vessels: They are long cylindrical, tube-like structures with lignified walls and wide central lumen. These cells are dead as these do not have protoplast. They are arranged in longitudinal series in which the partitioned walls (transverse walls) are perforated, and so the entire structure looks-like a water pipe. Their main function is the transport of water and minerals from root to leaf, and also to provide mechanical strength.

(iv) Xylem parenchyma: Its cells are living and thin-walled. The main function of xylem parenchyma is to store starch and fatty substances.

Question 3.
List out the differences< between mitosis and meipsis.

 Mitosis Meiosis 1. Occurs in somatic cells. Occurs in reproductive cells 2. Involved in growth and occurs continuously throughout life. Involved in gamete formation only during the reproductively active age. 3. Consists of single division. Consists of two divisions. 4. Two diploid daughter cells are formed. Four haploid daughter cells are formed. 5. The chromosome number in the daughter cell is similar to the parent cell (2n). The chromosome number in the daughter cell is just half (n) of the parent cell. 6. Identical daughter cells are formed. Daughter cells are not similar to the parent cell and are randomly assorted.

VII. Higher Order Thinking Skills :

Question 1.
What is the consequence that occurs if all blood platelets are removed from the blood?
Blood platelets play a major role in the clotting of blood whenever there is a wound/injury. If blood platelets are removed from the blood, clotting of blood will not occur. In case of any injury/surgery etc., blood will be lost from the body in excess and may even prove to be fatal.

2. Which are not true cells in the blood? Why?
Red blood cells or erythrocytes cannot be considered as true cells since they have a nucleus only in the early stages. A mature RBC lacks a nucleus which is the controlling centre of all living cells.

Intext Activities

ACTIVITY – 1
Rinse your mouth with water. Using a toothpick or ice-cream stick, scrap superficial cells from the inner side of the cheek and spread it on a clean glass slide. Dry the glass slide with the scrap cells taken from the inner side of the cheek. Add two drops of methylene blue stain. Identify the cells under low and high power of the microscope.
Solution:
1. Large irregularly shaped cells with cell walls.
2. Dark blue nucleus at the central part of each cell.
3. Lightly stained cytoplasm colour in each cell.

### 9th Science Guide Organization of Tissues Additional Important Questions and Answers

I. Choose the correct answer :

Question 1.
A meristematic tissue consists of
(a) immature cells that are capable of undergoing cell division.
(b) mature cells
(c) non-living cells
(d) sclerenchyma cells
(a) immature cells that are capable of undergoing cell division

Question 2.
Two long bones of the hand are dislocated in a person who met with an accident. Which among the following may be the possible reason?
(a) Tendon injury
(b) Break of skeletal muscle
‘(c) Ligament tear
(d) Rupture of Areolar tissue
(c) Ligament tear

Question 3.
Non-striated muscles are found in
(a) blood vessels
(b) gastric glands
(d) all of these
(d) all of these

Question 4.
(a) Sarcolemma
(b) Dendrite
(c) Myelin sheath
(d) Axon
(a) Sarcolemma

Question 5.
Cylindrical, unbranched multinucleated cells are
(a) striated muscle cells
(b) smooth muscles
(c) cardiac muscles
(d) none of the above.
(a) striated muscle cells

Question 6.
The matrix of the bone is rich in
(a) elastin
(b) reticular fibres
(c) collagen
(d) myosin
(c) collagen

Question 7.
Which muscles act involuntarily?
(i) Striated muscles
(ii) Smooth muscles
(iii) Cardiac muscles
(iv) Skeletal muscles
(a) (i) and (ii)
(b) (ii) and (iii)
(c) (iii) and (iv)
(d)(i) and (iv)
(b) (ii) and (iii)

Question 8.
Tendon connects
(a) cartilage with muscles
(b) bone with skeletal muscles
(c) ligament with muscles
(d) bone with bone
(b) bone with skeletal muscles

Question 9.
In a certain type of cell division, the diploid number of chromosomes is reduced to half. This kind of division occurs in
(a) testis
(b) ovary
(c) both ovary and testis
(d) all body cells
(c) both ovary and testis

Question 10.
……………… is derived from the ground meristem.
(a) Cortex
(b) Epidermis
(c) Xylem
(d) Cambium
(a) Cortex

Question 11.
The function of phloem fibres is …………….to the plant body
(a) passage of food
(b) Store food
(c) mechanical strength
(d) preparation of food
(c) mechanical strength

Question 12.
The …………….. epithelium is also known as pavement membrane.
(a) Ciliated
(b) Squamous
(c) Cuboidal
(d) Glandular
(b) Squamous

Question 13.
Elastic structures that connect bones to bones are called ………………..
(a) muscles
(b) tendons
(c) ligaments
(d) areolar tissue
(c) ligaments

Question 14.
………………… is seen in unicellular animals.
(a) Mitosis
(b) meiosis
(e) Amitosis
(d) none of the above
(c) Amitosis

Question 15.
The disappearance of spindle fibres is seen in …………….
(a) metaphase
(b) prophase
(c) anaphase
(d) telophase
(d) telophase

Question 16.
The ………………… is a single, long fiber like process that develops from the cyton.
(a) dendron
(b) axon
(c) dendrite
(d) neurilemma
(b) axon

Question 17.
Bouquet stage refers to ……………..
(a) diakinesis
(b) leptotene
(c) zygotene
(d) pachytene
(b) leptotene

Fill in the blanks :

1. The ……………. tissues are made up of more than one type of cells and these woks together as a unit.
complex

2. The two types of skeletal connective tissues are ……………. and …………….
bone, cartilage

3. Humans have 46 chromosomes. Their sperms and eggs will have ……………. chromosomes each.
23

4. During pairing of chromosomes in meiosis, the …………….. chromosomes come to lie side by side.
homologous

5. The word meristem is derived from a Greek word ………………
Meristos

6. Cork cambium is an example of ……………… meristem.
secondary

7. The meristem found at the base of intemodes is called ……………….
intercalary meristem

8. In apple, paranchyma stores ………………
sugar

9. Fibres are extensively longer ranging from 20 mm to 550 mm ……………….
corchorus capsularis (jute)

10. During mieosis in pachytene, stages the paired chromosomes are called ………………….
bivalents

11. Mitosis was discovered by …………………..
Flemming

12. Both smooth and cardiac muscles are …………….. in nature.
involuntary

13. ………………. is a non-flexible skeletal connective tissue.
Bone

14. ……………. acts as a fat reservoir.

15. …………….. epithelium is seen in sweat glands.
Cuboidal

16. Genetic variations occur in meiosis because of …………….
crossing over

III. State whether True or false. If false, write the correct statement:

1. Epithelial layer does not allow regulation of materials between the body and the external environment.
False.
Correct statement: Epithelium is involved in the absorption and elimination of waste.

2. Striated and non-striated tissues are types of epithelial tissues.
False.
Correct statement: They are types of muscular tissues.

3. Spindle formation occur in amitosis.
False.
Correct statement: Spindle formation occur in mitosis.

4. Movement of food in the alimentary canal is because of cardiac muscles.
False.
Correct statement: Movement of food is alimentary canal by the rhythmic con t no-tom and relaxation of the muscular nails of the alimentary canal.
Correct statement: Movement of food in the alimentary canal.

5. A mature RBC lacks a nucleus.
True

6. Excessive pulling of bones causes a sprain.
False.
Correct statement: Sprain is caused by excessive pulling of ligaments.

7. Glandular epithelium gives a stratified appearance.
False.
Correct statement: Compound epithelium given a stratified appearance.

8. Sieve cells have no companion cells.
True.

9. Conduction can be bidirectional in phloem tissue.
True.

10. White blood corpuscles contain respiratory pigment hemoglobin.
False.
Correct statement: Red blood corpuscles contain respiratory pigment hemoglobin.

IV. Assertion and Reason type:

Direction: In each of the following questions, a statement of Assertion is given and a corresponding statement of Reason is given just below it. Of statements, given below, mark the correct answer as
(a) Both Assertion and Reason are true and Reason is the correct explanation of Assertion.
(b) Both Assertion and Reason are true that Reason is not the correct explanation of Assertion.
(c) Assertion is true but Reason is false.
(d) Both Assertion and Reason are false.

Question 1.
Assertion: Non-striated muscles are said to be voluntary in nature.
Reason: Non-striated muscles are under the control of our will.
(d) Both Assertion and Reason are false

Question 2.
Assertion: Materials are exchanged between epithelial and connective tissues by diffusion.
Reason: Blood vessels are absent in epithelial tissue.
(a) Assertion and Reason are true and Reason is the correct explanation of Assertion

V. Answer in one or two sentences :

Question 1.
Name the two types of sclerenchyma cells.
Sclerenchyma cells are grouped into

1. fibres and
2. sclereids.

Question 2.
Name the components of xylem and phloem.
Xylem is composed of :

• Xylem tracheids
• Xylem fibres
• Xylem vessels
• Xylem parenchyma

Phloem is composed of:

• Sieve elements
• Companion cells
• Phloem fibres
• Phloem parenchyma

Question 3.
Name the tissue that connects muscle to bone in humans.
Tendons join skeletal muscles to bones in our body.

Question 4.
Name the tissue that stores excess fat in our body.

Question 5.
Name the connective tissue with a fluid matrix.
Blood and lymph

Question 6.
Name the tissue present in the brain.
Nervous tissue.

Question 7.
What is plate meristem?
These cells divide into two planes resulting in an increase in the area of an organ.
Eg: Leaf formation.

Question 8.
Differentiate collenchyma and sclerenchyma.

 Collenchyma Sclerenchyma It consists of living cells It consists of dead cells Cells contain protoplasm Cells do not possess living protoplast Cell walls are non-lignified Cell walls are lignified

Question 9.
Mention the type of epithelium seen in alveoli of lungs.,
Squamous epithelium.

Question 10.
Name the supportive connective tissues.
Cartilage and bone

Question 11.
Name the cartilage cells present in the matrix.
Chondrocytes.

Question 12.
What is the role of RBC?
RBC contains a respiratory pigment called hemoglobin which is involved in the transport of oxygen to tissues.

Question 13.
Mention the stages of meiotic Prophase -I.
Leptotene, Zygotene, Pachytene, Diplotene, Diakinesis.

Question 14.
What is the significance of Meiosis?
The constant number of chromosomes in a given species is maintained by meiotic division.

Question 15.
Draw a shoot apex and label the meristem’s parts.

Question 1.
How would you differentiate meristematic and permanent tissue?

 Meristematic tissue Permanent tissue Cytoplasm is dense, and vacuoles are nearly absent. Usually large central vacuole present in living permanent cells. Intercellular spaces absent. Intercellular spaces present. Component cells are small, spherical or polygonal and undifferentiated. Component cells are large, differentiated with different shapes. Cell wall is thin and elastic. Cell wall is thick. Nucleus is large and prominent. Nucleus is less conspicuous. Cells grow and divide regularly. Cells do not normally divide. Provides mechanical support and elasticity to the plant body. Provides only mechanical support.

Question 2.
Differentiate fibres from sclereids.

 Sclereids Fibres Usually broad Elongated narrow thread-like End walls blunt Usually with pointed ends. Occur singly Occur in bundles Deep pits Narrow pits

Question 3.
Which tissue is the main component of tendons and ligaments? How do they differ in function?
Dense Connective Tissue is a fibrous connective tissue densely packed with fibres and fibroblasts. It is the principal component of tendons and ligaments.

a. Tendons: Cord-like, strong, structures that join skeletal muscles to bones. Tendons have great strength and limited flexibility. They consist of parallel bundles of collagen fibres, between which are present rows of fibroblasts.

b. Ligaments: They are highly elastic structures and have great strength which connects bones to bones. They contain very little matrix. They strengthen the joints and allow normal movement.

Question 4.
What are the fibres present in the connective tissue proper?
Connective tissue proper: Connective tissue proper consists of collagen fibres, elastin fibres and fibroblast cells.

Areolar tissue: It has cells and fibres loosely arranged in a semi-fluid ground substance called matrix. It takes the form of fine threads crossing each other in every direction leaving small spaces called areolae. It joins skin to muscles, fills space inside organs and is found around muscles, blood vessels and nerves. It helps in repair of tissues after injury and fixes skin to underlying muscles.

Adipose Tissue: Adipose tissue is the aggregation of fat cells or adipocytes spherical or oval in shape. It serves as fat reservoir. The matrix consists of collagen fibres, elastin fibres and fibroblast cells.

Question 5.
How are collagen fibres organized in dense connective tissues?

• Dense connective tissue is a fibrous connective tissue densely packed with fibres and fibroblasts. It is the principal component of tendon and ligaments.
• Tendons consist of parallel bundles of collagen fibres, between which are present rows of fibroblasts.
• Ligaments are highly elastic structures and contain very little matrix.

Question 6.
Write one point of difference between
a) Bone and cartilage.
b) Simple and compound epithelial tissue.
a)

 Bone Cartilage It is solid, rigid, and strong, non-flexible skeletal connective tissue. It is a soft, semi-rigid, flexible skeletal connective tissue. The matrix of the bone is in the form of concentric rings called lamellae The matrix is composed of large cartilage cells called chondrocytes

b)

 Simple epithelium tissue Çompound epithelium tissue It is composed of a single layer of cells resting ón a basement membrane. It is composed of several layers of cells. Only the cells of the deepest layer rest on the basement membrane.

Question 7.
Why is blood considered to be a fluid connective tissue?

• The blood and the lymph are the fluid connective tissues which link different parts of the body. The cells of the connective tissue are loosely spaced and are embedded in an intercellular matrix.
• Blood contains corpuscles which are red blood cells (erythrocytes), white blood cells (leucocytes), and platelets. In this fluid connective tissue, blood cells move in a fluid matrix called plasma. The plasma contains inorganic salts and organic substances. It is a main circulating fluid that helps in the transport of nutrient substances.

Question 8.
Give the sequence of the events occurring during prophase of mitosis.

• During this stage, chromosomes become short and thick and are clearly visible inside the nucleus.
• Centrosome splits into two daughter centrioles and occupies opposite poles of the cell.
• Each centriole is surrounded by aster rays. Spindle fibres appear between the two centrioles.
• The nuclear membrane and nucleolus disappear gradually.

Question 9.
Why is meiosis called reductional division and mitosis as equational division?

• In mitosis one parent cell divides into two identical daughter cells, each with a nucleus having the same amount of DNA, same number of chromosomes and genes as the parent cells. It is therefore called an equational division.
• Meiosis is called reduction division because the chromosome number is reduced to haploid (n) from diploid (2n) in the daughter cells.

Question 10.
What is terminalization?
In the stage of diplotene of meiotic prophase I, chiasmata begin to move along the length of the chromosome from the centromere towards the end resulting in terminalization.

Question 11.
The chromosomes are visible as long paired twisted threads. The pairs so formed are called bivalents. Each bivalent now contains four chromatids (tetrad stage) in pachytene of mieotic prophase I. The condition of bivalent containing four chromatids are called tetrad stage.

Question 12.
What is crossing over?
During pachytene of mieotic prophase I, the chromatids break and the broken segments are interchanged between homologous chromosomes. The points of exchange are the chiasmata. This is called .crossing over.

Question 13.
What is bouquet stage?
During leptotene of mieotic prophase I, the chromosomes become uncoiled and assume long thread-like structures and take up a specific orientation inside the nucleus. They form a bouquet stage.

Question 14.
What is zygotene?
It is one of the stages of mieoticphophase I. Two homologous chromosomes approach each other and begin to pair. The pairing of homologous chromosomes is called synapsis.

Question 15.
Explain amitosis.
It is the simplest model of cell division and occurs in unicellular animals, aging cells and in foetal membranes. During amitosis, the nucleus elongates first, and a constriction appears in it which deepens and divides the nucleus into two, followed by this cytoplasm divides resulting in the formation of two daughter cells.

Question 16.
Write the salient features of the compound epithelium.

• It consists of more than one layer of cells and gives a stratified appearance. Hence, they are also known as stratified epithelial cells.
• The main function of this epithelium is to give protection to the underlying tissues against mechanical and chemical stress.
• They also cover the dry surface of the skin, the moist surface of the buccal cavity, and the pharynx.

Question 17.
Write a note the significance of mitosis.

• This equational division results in the production of diploid daughter cells (2n) with equal distribution of genetic material (DNA).
• In multicellular organisms growth, organ development and an increase in body size are accomplished through the process of mitosis.
• Mitosis helps in the repair of damaged and wounded tissues by the renewal of the lost cells.

Question 18.
Draw a neuron and label the parts.

Question 1.
What are meristems? Describe the distribution and functions of various types of meristems.
Meristematic tissues are group of immature cells that are capable of undergoing cell division. In plants, the meristem is found in zones where growth can take place. Example: apex of stem, root, leaf primordia, vascular cambium, cork cambium, etc.,

Types of Meristems based on position:
On the basis of their position in the plant, meristems are of three types: Apical meristem, Intercalary meristem, and Lateral meristem.

Apical meristem: These are found at the apices or growing points of root and shoot and bring about an increase in length.

Intercalary meristem: It lies between the region of permanent tissues and is part of the primary meristem. It is found either at the base of leaf e.g. pinus or at the base of internodes e.g. grasses.

Lateral Meristem: These are arranged parallel and causes the thickness of the plant part.

Functions: Meristems are actively dividing tissues of the plant, that are responsible for primary (elongation) and secondary (thickness) growth of the plant.

Question 2.
Give one reason for the following:
a. Blood is fluid connective tissue.
b. Skeletal muscles are voluntary muscles.
c. Heart muscles are involuntary in nature.
The blood and the lymph are the fluid connective tissues which link different parts of the body. The cells of the connective tissue are loosely spaced and are embedded in an intercellular matrix.

(a) Blood: Blood contains corpuscles which are red blood cells (erythrocytes), white blood cells (leucocytes), and platelets. In this fluid connective tissue, blood cells move in a fluid matrix called plasma. The plasma contains inorganic salts and
organic substances. It is a main circulating fluid that helps in the transport of nutrient substances.

(b) They work under our control and are also known as voluntary muscles. They are not under the control of our will and so are called involuntary muscles.

(c) Cardiac muscle: It is a special contractile tissue present in the heart. The muscle fibers are cylindrical, branched, and uninucleate The branches join to form a network called as itercalated disc which are unique distinguishing features of the
cardiac muscles. The contraction of cardiac muscle is involuntary and rhythmic.

Question 3.
Explain simple epithelium and its types.
Simple Epithelium :
1. It is formed of a single layer of cells. It forms a lining for the body cavities and ducts.
2. Simple epithelium is further divided into the following types.

• Squamous epithelium
• Cuboidal epithelium
• Columnar epithelium
• Ciliated epithelium
• Glandular epithelium

(i) Squamous epithelium :

• It is made up of thin, flat cells with prominent nuclei. These cells have irregular boundaries and bind with neighbouring cells.
• The squamous epithelium is also known as pavement membrane, which forms the delicate lining of the buccal cavity, alveoli of lungs, proximal tubule of kidneys, blood vessels etc.
• It protects the body from mechanical injury, drying and invasion of germs.

(ii) Cuboidal epithelium:

• It is composed of single layer of cubical cells.
• The nucleus is round and lies in the centre.
• This tissue is present in the thyroid vesicles, salivary glands, sweat glands, exocrine pancreas.
• It is also found in the intestine and tubular part of the nephron (kidney tubules) as microvilli that increase the absorptive surface area.
• Their main function is secretion and absorption.

(iii) Columnar epithelium:

• It is composed of a single layer of slender, elongated and pillar like cells.
• Their nuclei are located at the base.
• It is found lining the stomach, gall bladder, bile duct, small intestine, colon, oviducts and forms a mucous membrane. ‘
• They are mainly involved in secretion and absorption.

(iv) Ciliated epithelium :

• Certain columnar cells bear numerous delicate hair like out growths called ilia and are called ciliated epithelium.
• Their function is to move particles or mucus in a specific direction over the epithelium.
• It is seen in the trachea of wind-pipe, bronchioles of respiratory tract, kidney tubules and fallopian tubes of oviducts.

(v) Glandular epithelium :

• Epithelial cells are often modified to form specialized gland cells which secrete chemical substances at the epithelial surface.
• This lines the gastric glands, pancreatic tubules and intestinal glands.

Question 4.
Explain the components of phloem tissue.
Phloem is a complex tissue and consists of the following elements :
(i) Sieve elements
(ii) Companion cells
(iii) Phloem fibres
(iv) Phloem parenchyma

(i) Sieve elements :

• The conducting elements of phloem are collectively called as Sieve elements.
• Sieve tubes are elongated, tube-like slender cells placed end to end. The transverse walls at the ends are perforated and are known as sieve plates.
• The main function of sieve tubes is translocation of food, from leaves to the storage organs of the plants.

(ii) Companion cells : These are elongated cells attached to the lateral wall of the sieve tubes. A companion cell may be equal in length to the accompanying sieve tube element or the mother cell may be divided transversely forming a series of companion cells.

(iii) Phloem parenchyma : The phloem parenchyma are living cells which have cytoplasm and nucleus. Their function is to store food materials.

(iv) Phloem fibers : Sclerenchymatous cells associated with primary and secondary phloem are commonly called phloem fibers. These cells are elongated, lignified and provide mechanical strength to the plant body.

Question 5.
Write a note on blood and its components.
Blood is a fluid connective tissue.
Blood contains corpuscles which are red blood cells (erythrocytes), white blood cells (leucocytes) and platelets. In this fluid connective tissue, the blood cells move in a fluid matrix called. The plasma contains inorganic salts and organic substances. It is a main circulating fluid that helps in the transport of nutrient substances.

Red blood corpuscles (Erythrocytes):

• The red blood corpuscles are oval shaped, circular, biconcave disc-like and lack nucleus when mature (mammalian RBC).
• They contain a respiratory pigment called haemoglobin which is involved in the transport of oxygen to tissues.

White blood corpuscles (Leucocytes): They are larger in size, contain distinct nucleus and are colourless. They are capable of amoeboid movement and play an important ‘ role in body’s defense mechanism. WBC’s are of two types :
(i) Granulocytes.
(ii) Agranulocytes.

(i) Granulocytes have irregular shaped nuclei and cytoplasmic granules. They include the neutrophils, basophils and eosinophils. Agranulocytes lack cytoplasmic granules and include the lymphocytes and monocytes.

Blood platelets : They are minute, anucleated, fragile fragments of giant bone marrow called mega karyocytes They play an important role in blood clotting mechanism.

VIII. Higher Order Thinking Skills :

Question 1.
Identify the figure given below

(a) Label the parts A, B and C.
(b) What is the chemical composition of the tissue?
(a) T.S. of Bone
(A) Lamellae
(B) Lacunae
(C) Central (Haversian canal)
(b) The matrix of the bone is rich in calcium salts and collagen fibres which gives the bone its strength.
(c) C – Haversian canal

Question 2.
Identify figures A and B.

(a) …………… epithelium forms the outer lining of the buccal cavity.
(b) ………………. epithelium consist of ceils that are tall and pillar-like.
(c) Which one allows diffusion of substances?
(d) Which is called pavement epithelium?
(e) Which epithelium lines the gastrointestinal tract and epiglottis?
Figure A – Squamous Epithelium
Figure B. – Glandular epithelium
(a) Squamous
(b) Columnar
(c) Columnar epithelium
(d) Squamous epithelium
(e) Columnar epithelium

Question 3.
If cell (A) has undergone one mitotic division and another cell (B) has completed its meiotic division. The number of cells produced in A and B would be
Cell A: Cell B :
Cell A : 2 daughter cells.
Cell B : 4 daughter cells.

Question 4.
Identify the stage of mitosis from the below picture. List the chromosomal events in this stage.

Mitotic anaphase
(i) The centromeres attaching the two chromatids divide and the two daughter chromatids of each chromosome separate and migrate towards the two opposite poles.
(ii) The migration of the daughter chromosomes is achieved by the contraction of spindle fibres.

Question 5.
Identify the following relationship
Cuboidal : Epithelial
Cardiac : ………..
Granulocytes : …………
Osteocytes : ………….
Cardiac : Muscular
Granulocytes : Blood cells
Osteocytes : Bone cells

Question 6.
Umbilical cord blood is collected at the time of child birth and stored in stem cell banks? Reason out.

• Umbilical cord blood consists of stem cells, they are undifferentiated cells which undergo unlimited divisions and give rise to one or more different types of cells. – Embryonic stem cells differentiate into different tissues and organs.
• Stem cells can be used in the treatment of certain degenerative diseases in future.

Question 7.
How do WBC help in defence?
They are capable of amoeboid movement and play an important role. They engulf or destroy foreign bodies.

## Samacheer Kalvi 9th Science Guide Chapter 17 Animal Kingdom

Tamilnadu State Board New Syllabus Samacheer Kalvi 9th Science Guide Pdf Chapter 17 Animal Kingdom Text Book Back Questions and Answers, Notes.

## Samacheer Kalvi 9th Science Solutions Chapter 17 Animal Kingdom

### 9th Science Guide Animal Kingdom Text Book Back Questions and Answers

I. Choose the correct answer :

Question 1.
Find the group having only marine members.
(a) Mollusca
(b) Coelenterata
(c) Echinodermata
(d) Porifera
(d) Echinodermata

Question 2.
Mesoglea is present in
(a) Porifera
(b) Coelenterata
(c) Annelida
(d) Arthropoda
(b) Coelenterata

Question 3.
Which one of the following pairs is not a poikilothermic animal
(a) Fishes and Amphibians
(b) Amphibians and Aves
(c) Aves and Mammals
(d) Reptiles and Mammals
(c) Aves and Mammals

Question 4
Identify the animal having four chambered heart.
(a) Lizard
(b) Snake
(c) Crocodile
(d) Calotes
(c) Crocodile

Question 5
The animal without skull is
(a) Acrania
(b) Acephalia
(c) Apteria
(d) Acoelomate
(a) Acrania

Question 6.
Hermaphrodite organisms are
(a) Hydra, Tape worm, Earthworm, Amphioxus
(b) Hydra, Tape worm, Earthworm, Ascidian
(c) Hydra, Tape worm, Earthworm, Balanoglossus
(d) Hydra, Tape worm, Ascaris, Earthworm
b) Hydra, Tap worm, Earthworm, Ascidian

Question 7.
Poikilothermic organisms are
(a) Fish, Frog, Lizard, Man
(b) Fish, Frog, Lizard, Cow
(c) Fish, Frog, Lizard, Snake
(d) Fish, Frog, Lizard, Crow
(c) Fish, Frog, Lizard, Snake

Question 8.
Air sacs and Pneumatic bones are seen in
(a) fish
(b) frog
(c) bird
(d) bat
(c) Bird

Question 9.
Excretory organ of tape worm is
(a) flame cells
(b) nephridia
(c) body surface
(d) solenocytes
(a) Flame cells

Question 10.
Water vascular system is found in
(a) Hydra
(b) Earth worm
(c) Star fish
(d) Ascaris
(c) Starfish

II. Fill in the blanks :

1. The skeletal framework of Porifera is ……………..
spicules

2. Ctenidia are respiratory organs in ……………….
phylum mollusca

3. Skates are ………………. fishes.
cartilaginous

4. The larvae of an amphibian is …………………..
bilaterally symmetrical

5. ………………. are jawless vertebrates.
Cyclostomes

6. …………………… is the unique characteristic feature of mammal.
Placenta

7. Spiny anteater is an example for …………….. mammal.
egg-laying

III. State whether true or false. If false write the correct statement :

1. Canal system is seen in coelenterates.
False.
Correct statement: Canal system is seen in porifera

2. Hermaphrodite animals have both male and female sex organs.
True,

3. Trachea are the respiratory organ of Annelida.
False.
Correct statement: Trachea are the respiratory organ of Arthopoda.

4. Bipinnaria is the larva of Mollusca.
False.
Correct statement: Bipinnaria is the larva of star fish.

5. Balanoglossus is a ciliary feeder.
True.

6. Fishes have two chambered heart.
True.

7. Skin of reptilians are smooth and moist.
False.
Correct statement: Skin of cyclostomata are smooth and moist.

8. Wings of birds are the modified forelimbs.
True

9. Female mammals have mammary glands.
True.

IV. Match the following :

 PHYLUM EXAMPLES (A) Coelenterata (i) Snail (B) Platyhelminthes (ii) Starfish (C) Echinodermata (iii) Tapeworm (D) Mollusca (iv) Hydra

A – iv, B – iii, C – ii, D – i

Question 1.
Define taxonomy.
The theoretical study of classification includes its basic principles, procedures, and rules.

Question 2.
What is nematocyst?
The tentacles of organisms belonging to phylum Coelenterata bear stinging cells called cnidoblast or nematocyst.

Question 3.
Why coelenterates are called diploblastic animals?
The animals in phylum coelenterates have two layers the outer ectoderm and the inner endoderm in the body wall. So they are called diploblastic animals.

Question 4.
List the respiratory organs of amphibians.
Respiration is through by gills, skin, buccopharynx and lungs.

Question 5.
How does locomotion take place in starfish?
Locomotion is affected by tube feet.

Question 6.
Are jellyfish and starfish similar to fishes? If no justify the answer.

• Jellyfish is a coelenterate. Their bodies are made of calcium carbonate.
• Starfish fish is an echinoderm. Their bodies are made of calcium carbonate.
• Catfish is a fish species.
• Jellyfish and starfish are invertebrates.
• Fishes are vertebrates.

Question 7.
Why are frogs said to be amphibians?
The frogs have dual adaptation in land and aquatic environments. So they are called amphibians.

Question 1.
Give an account on phylum Annelida.

• These are bilaterally symmetrical, triploblastic, first true coelomate animals with an organ-system grade of organization.
• Body is externally divided into segments called metameres joined by ring-like structures called annuli.
• It is covered by a moist thin cuticle.
• Setae and parapodia are locomotor organs.
• Sexes may be separate or ünited (hermaphrodites).
e.g- Nereis, Earthworm, Leech.

Question 2.
Differentiate between flatworms and roundworms?

 Flatworms Roundworms a) They belong to Phylum Platyhelminthes. They belong to Phylum Aschelminthes. b) They are mostly parasitic. Exist as free-living soil forms or as parasites. c) Mostly hermaphrodites. Sexual dimorphism is seen. d) They are acoelomate organisms. They are pseudocoelomate organisms. e) The alimentary canal is absent or simple. Eg: Tapeworm. The alimentary canal is a straight tube. Eg: Roundworm.

Question3.
Outline the flow charts of Phylum Chordata.
Classification of phylum Chordata:

Question 4.
List five characteristic features of fishes.

• Fishes are poikilothermic, whose internal temperature varies, considerably.
• The body has a covering of scales.
• Body muscles are arranged into segments called myotomes.
• The body is differentiated into head, trunk and tail.
• Respiration is done by 5 to7 pairs of gills, which are covered by an operculum or sometimes maybe naked.

Question 5.
Comment on the aquatic and terrestrial habits of amphibians.
Aquatic habits of amphibians:

• The larva of amphibians (tadpole) lives in water and breathes with gills.
• External fertilization occurs in frog with water as a medium of fertilization.
• The adult frog has webbed feet to swim in water.
• The skin is moist and glandular which helps in Respiration.

Terrestrial habits of amphibians:

• The adults live on land and breathe through the lungs. Bucco-pharynx also helps in Respiration.
• The forelimbs are short and help to hop on land.

Question 6.
How are the limbs of the birds adapted for avian life?

1. Birds have a spindle-shaped body.
2. The forelimbs are modified as wings for aerial locomotion.
3. The air sacs present in the birds, make the bird lightweight.
4. The body is covered with feathers.

Question 1.
Describe the characteristic features of different Prochordates.
Prochordata :

• The urochordates are considered as the forerunner of vertebrates.
• Based on the nature of the notochord, protochordate is classified into subphylum Urochordata and subphylum Cephalochordata.
Phylum Hemichordata :
• Hemichordates are marine organisms with soft, vermiform and unsegmented body.
• They are bilaterally symmetrical, coelomate animals with non-chordate and chordate features.
• They have gill slits but do not have notochord.
• They are ciliary feeders and mostly remain as tubiculous forms, e.g- Balanoglossus (Acorn worms).
Subphylum Urochordata:
• Notochord is present only in the tail region of free-living larva, e.g. Ascidian
• Adults are sessile forms and mostly degenerate.
• The body is covered with a tunic or test.

Subphylum Cephalochordata :

• Cephalochordates are small fish like marine chordates with unpaired dorsal fins.
• The notochord extends throughout the entire length of the body. e.g. Amphioxus

Question 2.
Give an account on phylum Arthropoda.

• Arthropoda is the largest phylum.
• The organisms have jointed legs.
• The body is segmented into head, thorax and abdomen.
• The exoskeleton is made up of chitin.
• The coelomic cavity is filled with haemolymph (blood).
• They do not have defined blood vessels. This is called open circulatory system.
• The insects shed the exoskeleton and this process is called moulting.
• Small Arthropods absorb oxygen through the body and larger aquatic species breathe through book gills.
• Land Arthropods breathe through a system of tiny body tubes called tracheae.
• Excretion occurs through malphigian tubules and through green glands in crabs and prawns. .
• Insects, spiders, crabs, shrimps, butterflies, millipedes, centipedes, and scorpions are some arthropods.

Intext activities

ACTIVITY – 1

Observation :

• Scorpion
• Arachnid
• Cockroach
• Crab
• Crustacean
[End of the activity]

Question 1.
Which is not an insect?
(a) Housefly
(b) Bedbug
(c) Mosquito
(d) Spider
d) Spider

Question 2.
Which is not a feature of chordates?
(a) Green glands
(b) Sweat glands
(c) Sebaceous gland
(d) Mammary gland
(a) Green glands

Question 3.
Choose the correct terms related to Hemichordate
(a) Vermiform, unsegmented, bilaterally symmetrical, ciliary feeders
(b) Vermiform, segmented, triploblastic, ciliary feeders
(c) Vermiform, unsegmented, diploblastic, ciliary feeders
(d) Vermiform, unsegmented; triploblastic, filter feeders
a) Vermiform, unsegmented, bilaterally symmetrical, ciliary feeders

Question 4.
The …………. can swim faster than a cheetah.
(a) Sail fish
(b) Catfish
(c) Jelly fish
(d) Sucker fish
a) Sail fish

Question 5.
The biggest vertebrate animal is the ……………….
(a) Blue whale
(b) Dolphin
(c) Elephant
(d) Rhinoceros
(a) Blue whale

Question 6.
Who introduced binomial nomenclature?
(a) Huxley
(b) Carolus Linnaeus
(c) Nicolaus Copernicus
(d) Charles Darwin
(b) Carolus Linnaeus

Question 7.
What is the binomial name of tapeworm?
(a) Ascaris lumbricoides
(b) Taenia solium
(c) Lampito mauritii
(d) Hirudinaria granulosa
(b) Taenia solium

Question 8.
Which is the state bird of Tamil Nadu?
(a) Peacock
(b) Parrot
(c) Emerald dove
(d) Eagle
(c) Emerald dove

Question 9. ;
……………. is an example of bony fish.
(a) Mullets
(b) Sharks
(c) Skates
(d) Hagfish
(a) Mullets

Question 10.
The notochord extends throughout the entire length of the body.
(a) Acorn worms
(b) Lamprey
(c) Ascidian
(d) Amphioxus
(d) Amphioxus

Question 11.
Animals which possess notochord are called as …………………
(a) invertebrates
(b) non-chordates
(c) chordates
(d) all the above
(c) chordates

Question 12.
What ¡s the name of the bone which is filled with air?
(a) Flat bones
(b) Irregular bones
(c) Short bones
(d) Pneumatic bones
d) Pneumatic bones

Question 13.
_________ ¡s the unique characteristic feature of mammals.
(a) Placenta
(b) Egg
(c) Tail
(d) Ear
(a) Placenta

Question 14.
________ have gill slits but do not have notochord.
(a) Phylum Hemichordata
(b) Phylum Echirodermata
(c) Phylum Mollusca
(d) Phylum Annelida
Phylum Hemichordata

II. Fill In the blanks:

1. The binomial name of our National Bird is …………………………
pavocristatus

2. In mammals testis are enclosed by ………………….
scrotal sacs

3. In birds, the air sacs communicate with …………………
lungs

4. The animals belonging to phylunm …………….. are said to be soft-bodied.
mollusca

5. The name ………….. means “thousand legs”.
millipede

6. The skeletal framework of phylum Porifera is made up of ……………..
spicules

7. A true body cavity is located within ………………
mesoderm

8………………. separates the digestive tract from the body wall.
Coelom

9. ……………….. formed during embryonic development.
Notochord

10. …………….. is the largest phylum of the animal kingdom.
Arthropoda

11. ………………… is a fluid-filled body cavity.
Coelom

12. The body cavity of the phylum Aschelminthes is …………………….
pseudocoelom

13. The most common diseases caused by nematodes in human beings are …………and ……………
elephantiasis, ascariasis

14. Cyclostmes are ………………….
jawless vertebrates

15. Malphigian tubules also called as ……………….
green glands

16. Locomotion of phylum Echinodermata is affected by .
tube feet

III. Analogy:

Question 1.
Echinodermata: ________ : : Soft Bodies Animals: ________
Spiny Skinned Animals; Mollusca.

Question2.
Birds: _______ : : _________ : Cold-blooded.
Warm-blooded; Fishes.

IV. State whether true or false. If false write the correct statement:

1. Order is a number of related families having common characters are placed in an order.
True.

2. Tissue organization can be seen in phylum Porifera.
False.
Correct statement: Cellular grade of organization can be seen in phylum Porifera.

3. Aschelminthes is the largest phylum of the animal kingdom.
False.
Correct statement: Arthropods is the largest phylum of the animal kingdom.

4. In the animals belonging to phylum Echinodermata, the body is divided into head, muscular food and visceral mass………….
False.
Correct statement: In phylum mollusca, the body is divided into head, muscular food and visceral mass.

5. Setae and parapodia are locomotor organs of earthworms.
True.

6. Mammals have four-chambered Hearts.
True,

V. Match the following:

Question 1.

 (A) Cartilaginous (i) Mullets (B) Bony fishes (ii) Sharks (C) Pneumatic bones (iii) Reptiles (D) Three chambered heart (iv) Birds

A – i, B – ii, C – iv, D – iii

VI. Assertion and Reason type :

Question 1.
Assertion (A) : The Arthropods have an open circulatory system. .
Reason (R) : The cells and tissues are bathed in blood.
(a) A is right and R is wrong.
(b) A is the wrong R is right.
(c) A and R are wrong.
(d) A is right R explains A.
(d) A is right R explains A

Question 2.
Assertion (A) : Mammals give birth to their young ones.
Reason (R) : Platypus is an egg-laying mammal.
(a) A and R are correct.
(b) A and R are wrong.
(c) R explains A.
(d) A is the wrong R is right.
(a) A and R are correct

VII. Answer in one or two sentences :

Question 1.
Which organism is called Friends of farmers? Why?
Earthworms are called ‘Friends of the farmers’ because after digesting organic matter, earthworms excrete a nutrient-rich waste product called castings which are used as Vermicompost.

Question 2.
What are the sub-phylum of prochordates?
Sub phylum of prochordates are
Subphylum Cephalochordata
Subphylum Urochordata

Question 3.
Name the three germ layers.,
Ectoderm, mesoderm and endoderm

Question 4.
Name the locomotary organs seen in phylum protozoa.
Pseudopodia, cilia, or flagella.

Question 5.
Mention two special features of mammals.
(i) External ear or pinna is seen in most the mammals.
(ii) Presence of the placenta is a unique characteristic feature.

Question 6.
Write the binomials of a) Man b) Tapeworm
a) Homo sapiens
b) Taenia solium.

Question 7.
What is the binomial name?
Carolus Linnaeus introduced the method of naming the animals with two names. This is known as binomial name and is followed universally.
Eg: Binomial of frog is

Question 1.
How is the body wall of coelenterates arranged?
Body wall of coelenterate is disloblastic with two layers, namely the outer ectoderm and the inner endoderm, are separated by non-cellular jelly-like substance called mesoglea. Due to the presence of two layers in the body wall, they are said to be diploblastic animals.

Question 2.
What is polymorphism?
Many coelenterates exhibit polymorphism, which is the variation in the structure and function of the individuals of the same species. They reproduce both asexually and sexually, e.g. Hydra, Jellyfish.

Question 3.
What is the unique feature of chordates?
Presence of notochord is the unique feature of chordates.

Question 4.
On the basis of position of notochord, classify the different prochordates. Justify your answer.

 Subphyla of prochordates Position of notochord b) Cephalochordata The notochord is present only in the tail region of the free-living larva. e.g. Ascidian c) Urochordata The notochord extends throughout the entire length of the body. e.g. Amphioxus

Question 5.
List the integumentary glands of mammals.
Integumentary glands are seen in mammals:

• Sweat glands
• Sebaceous glands
• Scent glands
• Mammary glands are modified
• Integumentary glands

Question 6.
How is the reproductive characters of mammals different from those of aves.

 Mammals Aves (i) Mammals have paired sex organs, eggs are small with little or no yolk. (i) They are oviparous and lay eggs. (ii) They are viviparous and give birth to young one. (ii) Formation of placenta is not seen. The embryo is nourished,by egg yolk. Egg has an abundant quantity of yolk. (iii) Formation of placenta is a special feature. The tissue connects the foetus to maternal tissues.

Question 7.
Mention two characteristic features of phylum Echinodermata.
They have a water vascular system which is a unique feature. Locomotion is affected by tube feet.

Question 8.
Mention two features seen in Aves to aid in flying.

• The forelimbs are modified into wings for flight.
• Bones are filled with air (pneumatic bones), which reduces body weight.

Question 9.
Why is crocodile unique among reptiles?
It has a four-chambered heart whereas the reptiles have a three-chambered heart.

Question 10
Why are eggs of reptiles covered with shell unlike eggs of amphibians?
First-class of vertebrates adapted for terrestrial life and lay their eggs with tough outer Shell e.g Calotes, Lizard, Snake, Tortoise, Turtle. Hence the eggs are covered with shells to protect them. Whereas amphibians eggs are laid in water.

Question 11.
What are pneumatic bones?
The bones are filled with air. So they are called pneumatic bones and are seen in aves.

Question 1.
Write a note on mammals.

• Mammals are -warm-blooded animals.
• The skin is covered with hair. It also bears sweat and sebaceous (oil) glands.
• The body is divisible into head, neck, trunk and tail.
• Females have mammary glands, which secrete milk for feeding the young ones.
• The external ear or pinnae is present.
• Heart is four-chambered and they breathe through lungs.
• Except egg-laying mammals (Platypus, and Spiny anteater), all other mammals give birth to their young ones (viviparous).
• Placenta is the unique characteristic feature of mammals, e.g Rat, Rabbit, Man.

Question 2.
Write a note on aves.

• Birds are homeothermic (warm-blooded) animals with several adaptations to fly.
• The spindle or boat-shaped body is divisible into head, neck, trunk and tail.
• The body is covered with feathers. Forelimbs are modified into wings for flight.
• Hindlimbs are adapted for walking, perching or swimming.
• The respiration is through lungs, which have air sacs.
• Bones are filled with air (pneumatic bones), which reduces body weight.
• They lay large yolk laden eggs.
• They are covered by hard calcareous shell, e.g. Parrot, Crow, Eagle, Pigeon, Ostrich.

Question 3.
Outline the flow chart of invertebrate phyla.

## Samacheer Kalvi 9th Science Guide Chapter 19 Plant Physiology

Tamilnadu State Board New Syllabus Samacheer Kalvi 9th Science Guide Pdf Chapter 19 Plant Physiology Text Book Back Questions and Answers, Notes.

## Tamilnadu Samacheer Kalvi 9th Science Solutions Chapter 19 Plant Physiology

### 9th Science Guide Plant Physiology Text Book Back Questions and Answers

I. Choose the correct answer :

Question 1.
The tropic movement that helps the climbing vines to find a suitable support is …………….
(a) phototropism
(c) thigmotropism
(b) geotropism
(d) chemotropism
(c) thigmotropism

Question 2.
The chemical reaction occurs during photosynthesis is .
(a) CO2 is reduced and water is oxidized
(b) water is reduced and CO2 is oxidized
(c) both CO2 and water are oxidized
(d) both CO2 and water are produced
(a) CO2 is reduced and water is oxidized

Question 3.
The bending of root of a plant in response to water is called …………………….
(a) Thigmonasty
(b) Phototropism
(c) Hydrotropism
(d) Photonasty
(c) Hydrotropism

Question 4.
A growing seedling is kept in the dark room. A burning candle is placed near it for a few days. The tip part of the seedling bends towards the burning candle. This is an example of ……………
(a) Chemotropism
(b) Geotropism
(c) Phototropism
(d) Thigmotropism
(c) Phototropism

Question 5.
The root of the plant is …………………
i) positively phototropic but-negatively geotropic
ii) positively geotropic but negatively phototropic
iii) negatively phototropic but positively hydrotropic
iv) negatively hydrotropic but.positively phototropic
(a) (i) and (ii)
(b) (ii) and (iii)
(c) (iii) and (iv)
(d) (i) and (iv)
(b) (ii) and (iii)

Question 6.
The non-directional movement of a plant part in response to temperature is called………………..
(a) Thermotropism
(b) Thermonasty
(c) Chemotropism
(d) Thigmonasty
(b) Thermonasty

Question 7.
Chlorophyllin a leaf is required for …………………
(a) photosynthesis
(b) tropic movement
(c) transpiration
(d) nastic movement
(a) photosynthesis

Question 8.
Transpiration takes place through ………………..
(a) fruit
(b) seed
(c) flower
(d) stomata
(d) stomata

II. Fill in the blanks :

1. The shoot system grows upward in response to ………………..
light

2. ………………..is positively hydrotropic as well as positively geotropic.
root

3. The green pigment present in the plant is………………..
chlorophyll

4. The solar tracking of sunflower in accordance with the path of sun is due to …………………
phototropism:

5. The response of a plant part towards gravity is ………………..
geotropism

6. Plants take in carbon dioxide for photosynthesis but need ……………….. for their living.
oxygen

III. Match column A with column B

 Column A Column B 1. Roots growing downwards into soil. Positive phototropism 2. Shoots growing towards the light. Negative geotropism 3. Shoots growing upward. Negative phototropism 4. Roots growing downwards away from light. Positive geotropism

 Column A Column B 1. Roots growing downwards into soil. Positive geotropism 2. Shoots growing towards the light. Positive phototropism 3. Shoots growing upward. Negative geotropism 4. Roots growing downwards away from light. Negative phototropism

IV. State whether true or false. If false, correct the statement:

1. The response of a part of plant to the chemical stimulus is called phototropism.
False.
Correct statement : The response of a plant part to the chemical stimulus is called Itemoiropisin.

2. Shoot is positively phototropic and negatively geotropic.
True.

3. When the weather is hot, water evaporates lesser which is due to opening of stomata.
False.
Correct statement: When the weather is hot, water evaporates more but stomata begin to close to reduce evaporation.

4. Photosynthesis produces glucose and carbon dioxide.
False.
Correct statement: Photosynthesis produces glucose and oxygen.

5. Photosynthesis is important in releasing oxygen to keep the atmosphere in balance.
True

6. Plants lose water when the stomata on leaves are closed.
False.
Correct statement: Plants lose water when the stomata on leaves are open.

Question 1.
What is nastic movement?
Non-directional response to the stimulus is called Nastic movements.

Question 2.
Name the plant part
a) Which bends in the direction of gravity but away from the light.
b) Which bends towards the light but away from the force of gravity.
a) Root system
b) Shoot system.

Question 3.
Differentiate phototropism from photo nasty.
Phototropism:

1. Movement of a plant part towards the light.
2. Eg: Shoot of a plant.

Photonasty:

1. Movement of a plant part is a response to light.
2. Eg: Moonflower, Taraxacum Officinale.

Question 4.
Photosynthesis converts energy X into energy Y.
a) What are X and Y?
b) Green plants are autotrophic in their mode of nutrition. Why?
a) X → light energy,
Y → Chemical energy.
b) Green plants are autotrophic in their mode of nutrition because they prepare then- own food materials through photosynthesis.

Question 5.
Define transpiration.
The loss of water in the form of water vapour from the aerial parts of the plant body is called Transpiration.

Question 6.
Name the cell that surrounds the stoma.
Each stomata is surrounded by guard cells.

Question 1.
Give the technical terms for the following :
a) Growth dependent movement in plants.
b) Growth independent movement in plants.
a) Tropic movements
b) Nastic movements

Question 2.
Explain the movement seen in Pneumatophores of Avicennia.

• Pneumato[hores are specialized roots that can involve in the respiration of plants,
• This type of roots intakes the gas through its lenticel. a small hole in their both.

Question 3.
Fill in the blanks:

Question 4.
What is chlorophyll?
Chlorophyll is a green pigment present in all green plants with is responsible for the absorption of light to provide energy for photosynthesis.

Question 5.
Name the part of plant which shows positive geotropism. Why?
Root shows positive geotropism because of the unidirectional movement in response to gravity.

Question 6.
What is the difference between the movement of flowers in the sunflower plant and the closing of the leaves in the Mimosa pudica?
Movement of flower in sunflower plant:
In sunflower plant the stem tip follows the path of the sun from dawn to dusk (East to est) and in night it moves from West to East. This is a growth movement and takes place in response to the stimulus ‘light’. It is an example of tropic movement in response to light and is called phototropism.

Closing of the leaves in the Mimosa pudica :
The closing of leaves in Mimosa pudica occurs in response to touch. It is not a growth movement and occurs independently of the direction of stimulus. This is nastic movement . and is called Thigmonasty.

Question 7.
Suppose you have a rose plant growing in a pot, how will you demonstrate transpiration in it?
Tie a plastic bag over leaves of rose plant and place in sunlight. After a few hours, we see water condensing inside the plastic bag. This is due to loss of water in the form of water vapour, which condenses into water. This is due to transpiration.

Question 8.
Mention the differences between stomatal and lenticular transpiration.
Stomatal transpiration :

1. Loss of water from plants through stomata.
2. 90-95% of transpiration in a plant takes place through stomata only.

Lenticular transpiration :

1. Loss of water from plants as vapour through the lenticels.
2. A very small percentage of water is lost by through plants lenticular transpiration.

Question 9.
To which directional stimuli do (a) roots respond (b) shoots respond?
(a) Roots respond positively geostrophic and negatively phototrophic.
(b) Shoots respond negatively geostrophic and positively phototrophic.

Question 1.
Differentiate between tropic and nastic movements
Tropic movements

1. Unidirectional response to the stimulus.
2. Growth dependent movements.
3. More or less permanent and irreversible.
4. Found in all plants.
5. Slow action.

Nastic movements :

1. Non-directional response to the stimulus
2. Growth independent movements. –
3. Temporary and reversible.
4. Found only in a few specialized plants.
5. Immediate action.

Question 2.
How will you differentiate the different types of transpiration?
There are three types of transpiration:
Stomatal transpiration: Loss of water from plants through stomata. It accounts for 90- 95% of the water transpired from leaves.
Cuticular transpiration: Loss of water in plants through the cuticle.
Lenticular transpiration: Loss of water from plants as vapour through the lenticels. The lenticels are tiny openings that protrude from the barks in woody stems and twigs as well as in other plant organs.
But transpiration is necessary for the following reasons.

1. It creates a pull in leaf and stem.
2. It creates an absorption force in roots.
3. It is necessary for a continuous supply of minerals.
4. It regulates the temperature of the plant.

VIII. Higher Order Thinking Skills:

Question 1.
There are 3 plants A, B and C. The flowers of A open their petals in bright light during the day but closes when it gets dark at night. On the other hand, the flowers f of plant B open their petals at night but closes during the day when there is a bright light. The leaves of plant C fold up and droop when touched with fingers or any other solid object.
(a) Name the phenomenon shown by the flowers of plants A and B.
(b) Name one plant each which behaves like the flowers of plant A and B.
(c) Name the phenomenon exhibited by the leaves of plant C.
(a) Photonasty
(b) Plant A – Common Dandelion – Taraxacum officinale
Plant B – Moonflower – Ipomoea alba
(c) Nyctinasty

Question 2.
Imagine that student A studied the importance of certain factors in photosynthesis.
He took a potted plant and kept it in dark for 24 hours. In the early hours of the next
morning, he covered one of the leaves with dark paper in the centre only. Then he placed the plant in sunlight for a few hours and tested the leaf which was covered
with black paper for starch.
(a) What aspect of photosynthesis was being investigated?
(b) Why was the plant kept in the dark before the experiment?
(c) How will you prove that starch is present in the leaves?
(a) Necessity of light as a factor for Photosynthesis.
(b) To make the plant starch-free before starting the experiment. After the experiment, if starch is found in the leaf it will be the starch prepared by leaves during the experiment only.
(c) Presence of starch in the leaves can be proved by doing the starch test.

• The potted plant is kept in bright sunlight for 4 to 6 hours.
• The selected covered leaf is plucked and the black paper is removed.
• The leaf is immersed in boiling water for a few minutes and then in alcohol to remove chlorophyll.
• The leaf is now tested with iodine solution for the presence of starch.
• The covered part of the leaf does not turn blue-black whereas the uncovered part of the leaf turns blue-black colour.
• The covered part of the leaf which did not receive the sunlight was unable to synthesize starch.
• Hence it does not turn blue-black colour.
• But the uncovered part of the leaf which received sunlight was able to synthesize starch and so it turns blue-black in colour.

Intext Activities

ACTIVITY – 1

Take a glass trough and fill it with sand. Keep a flower pot containing water, plugged at the bottom at the centre of the glass trough. Place some soaked pea or bean seeds around the pot in the sand. What do you observe after 6 or 7 days? Record your observation.

Aim : To demonstrate hydrotropism.
Materials required : Glass trough, sand, flower pot, plugged at the bottom, pea or bean seeds and water.

Procedure :

1. A glass trough is taken and is filled with sand. A flowerpot containing water plugged at the bottom is kept at the centre of the glass trough.
2. Soaked pea or bean seeds are placed around the pot in the sand. It is observed after 6 or 7 days.

Observation: Observed that radicle has grown towards the pot and moisture instead of growing vertically downward.
Inference: It proves that primary root is positively hydrotropic.
Result: Hydrotropism has been demonstrated by showing positive hydrotropism in roots.

[End of the activity]

ACTIVITY – 2

Take pea seeds soaked in water overnight. Wait for the pea seeds to germinate. Once the seedling has grown put it in a box with an opening for light on one side. After few hours, you can clearly see how the stem has bent and grown towards the light.

Aim : To demonstrate phototropism.
Materials required : Box, water, light and pea seeds.

Procedure:

1. Take pea seeds soaked in water overnight. Wait for the pea seeds to germinate.
2. Once the seedling has grown put it in a box with an opening for light on one side.
3. After few hours, you can clearly see how the stem has bent and grown towards the light.

Observation : Observed that movement of a stem of a plant (pea seeds) towards light moist condition. This is the way a new plant develops from a seed.
Inference : Positive phototropism of a plant has been demonstrated.

[End of the activity]

ACTIVITY – 3

Pluck a variegated leaf from Coleus plant kept in sunlight. De- starch it by keeping in dark room for 24 hours. Draw the picture of this leaf and mark the patches of cholorphyll on the leaf. Immerse the leaf in boiling water followed by alcohol and test it for starch using iodine solution. Record your observation.

Aim : To show that chlorophyll is essential for photosynthesis.
Materials required : Plant with variegated leaves, boiling water, alcohol and iodine solution.

Procedure:
Variegated leaf is plucked from Coleus plant kept in sunlight. It isde-starched by keeping it in dark room for 24 hours. The picture of this leaf is drawn and the patches of cholorphyll on the leaf are marked. After immersing the leaf in boiling water followed by alcohol it is tested for starch with iodine solution.

Observation : The patches of the leaf with chlorophyll turn blue-black. The other portions remain colourless.
Inference: The chlorophyll is essential for photosynthesis.

ACTIVITY – 4

Place a potted plant in a dark room for about 2 days to de-starch its leaves. Cover one of its leaves with the thin strip of black paper as shown in the picture, make sure that the leaf is covered on both sides. Keep the potted plant in bright sunlight for 4 to 6 hours. Pluck the selected covered leaf and remove the black paper.
Immerse the leaf in boiling water for a few minutes and then in alcohol to remove chlorophyll. Test the leaf now with iodine solution for the presence of starch. The covered part of the leaf does not turn blue-black whereas the uncovered part of the leaf turns blue-black colour. Why are the changes in colour noted in the covered and uncovered part of the leaf?

Aim : To show that light is essential for photosynthesis.
Materials required : Covered leaf, boiling water, alcohol and iodine.

Procedure:

1. A potted plant is placed in a dark room for about 2 days to de-starch its leaves.
2. One of its leaves is covered with a thin strip of black paper as shown in the picture.
3. Make sure that the leaf is covered on both sides.
4. The potted plant is kept in bright sunlight for 4 to 6 hours.
5. The selected covered leaf is plucked and the black paper is removed.
6. Th e leaf is immersed in boiling water for a few minutes and then in alcohol to remove chlorophyll.
7. The leaf is now tested with iodine solution for the presence of starch.

Observation : The covered part of the leaf does not turn blue-black whereas the uncovered part of the leaf turns blue black colour. The covered part of the leaf which did not receive sunlight was unable to synthesize starch.
Inference : The light is essential for photosynthesis.

### 9th Science Guide Plant Physiology in Animals Additional Important Questions and Answers

I. Choose the correct answer :

Question 1.
The bending of root of a plant in response to water is called …………………..
(a) thigmonasty
(b) phototropism
(c) hydrotropism
(d) photonasty
(c) hydrotropism

Question 2.
A growing seedling is kept in the dark room. A burning candle is placed near it for a few days. The top part of the seedling bends towards the burning candle. This is an example of ……………………
(a) chemotropism
(b) thigmotropism
(c) phototropism
(d) geotropism
(c) phototropism

Question 3.
The root of the plant is ……………………
(i) positively phototropic but negatively geotropic.
(ii) positively geotropic but negatively phototropic.
(iii) negatively phototropic but positively hydrotropic.
(iv) negatively hydrotropic but positively phototropic.
(a) (i) and (ii)
(b) (ii) and (iii)
(c) (iii) and (iv)
(d) (i) and (iv)
(b) (ii) and (iii)

Question 4.
The plant part which exhibits negative geotropism is ……………………
(a) root
(b) stem
(c) branch
(d) leaves
(b) stem

Question 5.
The non-directional movement of a plant part in response to temperature is called…………………..
(a) thermotropism
(b) thermonasty
(c) chemotropism
(d) thigmonasty
(b) thermonasty

Question 6.
Sunflowers open the petals in bright light during the day time but close the petals in dark at night. This response of sunflowers is called ……………………
(a) geonasty
(b) thigmonasty
(c) chemonasty
(d) photonasty
(d) photonasty

Question 7.
During photosynthesis plants exhale ……………………
(a) Carbon dioxide
(b) oxygen
(c) hydrogen
(d) helium
(b) oxygen

Question 8.
Chlorophyll in a leaf is required for ……………………
(a) photosynthesis
(b) transpiration
(c) tropic movement
(d) nastic movement
(a) photosynthesis

Question 9.
A plant is kept in a dark room for about 24 hours before conducting any experiment on photosynthesis in order to ……………………
(a) remove chlorophyll from the leaf
(b) remove starch from the leaves
(c) ensure that photosynthesis occurred
(d) to prove transpiration
(b) remove starch from the leaves

Question 10.
Transpiration takes place through ……………………
(a) fruit
(b) seed
(c) flower
(d) stomata
(d) stomata

Question 11.
Thigmonasty can be seen in ……………………
(a) Mimosa pudica
(b) Taraxacum officinale
(c) Ipomea alba
(d) Rhizophora
(a) Mimosa pudica

Question 12.
The venus flytrap plants are examples for …………………..
(a) chemotropism
(b) thigmonasty
(c) hydrotropism
(d) thigmotropism
(b) thigmonasty

Question 13.
………………….. flowers bloom as the temperature increases.
(a) Rose
(b) Jasmine
(c) Lilly
(d) Tulip
(d) Tulip

Question 14.
Only green plants have the unique capacity to release ………………….. into the atmosphere.
(a) nitrogen
(b) oxygen
(c) carbon dioxide
(d) ozone
(b) oxygen

Question 15.
The end product of photosynthesis is ……………………
(a) glucose
(b) sucrose
(c) fructose
(d) none of the above
(a) glucose

II. Fill in the blanks :

1. The minerals like nitrogen, potassium and phosphorus, are required in substantial quantity by the plants are called …………………..
macronutrients

2. The solar tracking of sunflower in accordance with the path of sun is due to ………………………
phototropism

3. The response of a plant part towards gravity is ………………………
geotropism

4. When the leaves of a sensitive plant are touched with a finger, they fold up and when light fades at dusk the petals of a sunflower. These two plants show ……………………..and ……………………..movements.
thigmonastic, photonastic

5. Opening and closing of Moon flower is not a tropism because the movement in this is……………………..
independent of stimulus

6. The raw materials for photosynthesis are …………………….. and ………………………
carbon dioxide, water

7. When iodine solution is added for testing starch, part of the leaf with …………………….. turn blue- black colour.
starch

8. In leaves, the food is stored in the form of……………………..
starch

9. Plants may inhale carbon dioxide for photosynthesis but need ……………………..for their living.
oxygen

10. Plants utilize only ……………………..% of the absorbed water for photosynthesis and the other activities.
1

11 . Plants inhale and exhale continuously through the . ……………………..
stamata

12. The bending of shoot towards light is due to the hormone ……………………..
auxin

13. Heliotropism is a kind of ……………………..
phototropism

14. The ……………………..plant exhibits one of the fastest known nastic movements.
venus flytrap

15. Chlorophyll differs from haemoglobin by the presence of its central molecule ……………………..
magnesium

16. Plants exchange gases ……………………..continuously through these stomata.
CO2 to O2

17. Guard cells help in regulating the ……………………..
rate of transpiration

III. Analogy :

Question 1.
Towards a stimulus : ……………….:: Away from the stimulus : Negative tropism
Positive tropism

Question 2.
Hydrotropism : Response towards water :: Phototropism : …………..
Response towards light

Question 3.
Photosynthesis : ……………….. :: Transpiration : Stomata
Green leaves

IV. State whether the following statements are true or false. If false, write the correct statement :

1. Scientific term used to represent the bending of roots towards water is called geotropism.
False.
Correct statement: Scientific term used to represent the bending of roots towards water is called hydrotropism.

2. When the leaves of Mimosa pudica plant are touched with the finger, they fold up quickly.
True.
Correct statement: This is an example of thigmonasty.

3. The petals of moon flower open up in morning and closes in the evening. This is called photonasty.
False.
Correct statement :The petals of moon flower dost ‘ in the morning and opens up in the evening. This is called photonasty.

4. Photosynthesis produces glucose and carbon dioxide.
False.
Correct statement: Photosynthesis produces glucose and oxygen.

5. Photosynthesis is important in releasing oxygen to keep the atmosphere in balance.
True.

6. Plants lose water when the stomata on leaves are closed.
False.
Correct statement: Plants will not lose water when the stomata on leaves are closed.

V. Assertion and reason :

Question 1.
Assertion (A) : If the plant part moves in the direction of gravity, it is called positive geotropism.
Reason (R) : Stem shows positive geotropism.
(a) A and R are incorrect
(b) A is incorrect, R is correct
(c) A is correct, R is incorrect
(d) Both A and R are correct
(c) A is correct, R is incorrect

Question 2.
Assertion (A) : The loss of excess water from the aerial parts of the plant in the form of water vapour is known as transpiration.
Reason (R) : Stomata of the leaf perform transpiration.
(a) A and R are incorrect
(b) A is incorrect, R is correct
(c) A is correct, R is incorrect
(d) Both A and R are correct
(d) Both A and R are correct

Question 1.
Write the scientific terms used to represent the following:
(a) Growing of roots towards the gravity.
(b) Bending of roots towards the water.

(a) Positive geotropism
(b) Positive hydrotropism.

Question 2.
Observe the given picture.
(a) Identify this plant. What type of special movement is shown by this plant?
(b) What are the other movements seen in this plant?
(a) Mimosa pudica.
Special movement shown by the plant: Just a casual touch is enough to make the leaves of Mimosa pudica (Touch-me- not plant) fold up and droop. This is described as seismonasty or thigmonasty.
Movements which are not directed towards stimuli but are independent of the stimulus direction are called as nastie movements. They may or may not be growth movement.

(b) The foliage of Mimosa closes during darkness and reopens in the presence of light. Note : The ‘rapid movement of in leaflets in Mimosa is rare in the plant kingdom and is related to changes in turgor pressure.

Question 3.
What is the end product of photosynthesis?
The end product of photosynthesis is glucose which is converted into starch and stored in the plant parts.

Question 4.
Name the minute openings seen on the lower surface of the leaf.
Stomata are the minute openings seen on the lower surface of the leaf.

Question 5.
Give the scientific terms for the following:
(a) Growth dependent movement in plants.
(b) Growth independent movement in plants.
(a) Tropic movements
(b) Nastie movements.

Question 6.
Study the pictures below and then complete the table by putting a plus (+) if the shoot or root grows towards the stimulus and a minus (-) if it grows away from it.

Question 7.
What is the other name for thigmonasty?
Seismonasty.

Question 8.
Which flowering plant shows photonasty just opposite to that of Dandelion?
Moon flower.

Question 9.
Give an example for negative hydrotropism.
Growth of certain fungal hyphae away from the source of water/moisture.
Note : No clear evidences of negative hydrotropism.

Question 10.
Which gas is evolved during photosynthesis?
Oxygen.

Question 11.
Give an example for micronutrients.
Zinc.

Question 12.
What does a Mimosapudica plant do in response to touch? What is the phenomenon known as?
In response to touch, the leaves of the plant Mimosa pudica fold up and droop. The movement is known as seismonasty or thigmonasty.

Question 13,
(i) What happens to the dandelion flower
(a) During the daytime?
(b) At night?
(ii) What is the phenomenon known as?
(i) (a) The dandelion flower unfolds.
(b) The dandelion flower closes.
(ii) The phenomenon is known as photonasty.

Question 14.
Define photosynthesis.
‘Photo’ means Tight’ and ‘synthesis’ means ‘to build’ thus photosynthesis literally means ‘building up with the help of light’. During this process, the light energy is converted into chemical energy. Green plants are autotrophic in their mode of nutrition because they prepare their food materials through a process called photosynthesis.\

Question 15.
Draw the structure of stomata and label the parts.

Question 16.
Complete the following table with the different types of tropism:

Question 17.
Label the diagram with the raw materials and products of photosynthesis.

A. Carbon dioxide
B. Water
C. Glucose
D. Oxygen

Question 18.
Give an example for the movement of plant part which is very quick and can be observed easily.
Just a casual touch is enough to make the leaves of Mimosa pudica fold up and droop. This takes place quickly and can be easily observed.

Question 19.
Name the cell that surrounds the stoma.
Guard cells.

Question 20.
Give an example for chemotropism.
During fertilization, pollen tube grows down the style in response to the sugars in the style is an example of chemotropism.

Question 21.
Give the overall equation for photosynthesis.

Question 22.
Guard cells of stomata are green but cannot photosynthesize? Give reason.
The enzymes needed for photosynthetic reactions are absent and hence guard cells cannot photosynthesize. _ .

Question 23.
Why do roots of halophytes show negative geotropism.
The roots turn 180° upright for respiration.

Question 24.
Why do stems show postive phototropism?

• Stem growing up and towards light is more likely to get sunlight for photosynthesis and display its flowers prominently for pollinators to arrive.
• It also has better chance of spreading its seeds.

Question 25.
Mention four factors required for photosynthesis?
Chlorophyll, Water, Carbon dioxide and Light.

Question 26.
Why is transpiration called as necessary evil?
Water is lost by transpiration but still it is a necessary process since it gives the following advantages to the plant.

• Creates an absorption force in roots to suck more water form the soil.
• Regulates the temperature of the plant. Hence transpiration is said to be a necessary evil.

Question 27.
What are stomata?
The leaves have tiny holes, t ailed slomaia, through which the exchange of air takes place. The leaves have tiny, microscopic pores called stomata. Water evaporates through these stomata. Each stomata is surrounded by guard cells. These guard cells help in regulating the rate of transpiration by opening and closing of stomata.

Question 28.
Write the scientific terms used to represent.
Leaves fold up and droop in touch-me-not plant Mimosa pudica Ans. Thigmonasty or Seismonasty.
Example: Brunnichia ovata and Mimosa pudica.

Question 1.
Write a note on Transpiration.

• The loss of water in the form of wate r vapour from the aerial parts of the plant body is called as transpiration.
• The leaves have tiny, microscopic pores called stomata.
• Water evaporates through these stomata. Each stomata is surrounded by guard cells.
• These guard cells help in regulating the rate of transpiration by opening and closing of stomata.

Question 2.
Write the types of tropism.
Types of Tropism :
Based on the nature of stimuli, tropism can be classifi ed as follows.
Phototropism : Movement of a plant part towards light, e.g. shoot of a plant.
Geotropism : Movement of a plant in response to gravity, e.g. root of a plant.
Hydrotropism : Movement of a plant or part of a plant towards water, e.g root of a plant.
Thigmotropism : Movement of a plant part due to touch, e.g. climbing vines.
Chemotropism : Movement of a part of plant in response to chemicals, e.g growth of a pollen tube in response to sugar present on the stigma.

Tropism is generally termed positive if growth is towards the signal and negative if it is away from the signal. Shoot of a plant moves towards the light, the roots move away. Th us the shoots are positively phototropic.

Usually shoot system of a plant is positively phototropic and negatively geotropic and root system is negatively phototropic and positively geotropic.

VIII. Higher Order Thinking Skills :

Question 1.
While conducting experiments to study the effects of various stimuli on the plants, it was observed that the roots of a plant X grow and bend towards two stimuli A and B but bend away from a third stimulus C. The stem of the plant X however bends ” away from stimulus A and B but bends towards the stimulus C. The stimulus B is known to act on the roots due to factors related with Earth. Keeping these points in mind, answer the following questions:
(a) What could be stimulus A ?
(b) Name the stimulus seen in B.
(c) What could be stimulus-C?
(a) Stimulus A – Water
(b) Stimulus B – Gravity
(c) Stimulus C – Light

Question 2.
An organism A which cannot move from one place to another makes a simple food B from the substances C and D available in the environment. This food is made in the presence of green coloured substance E present in organs F in the presence of light energy in a process called G. Some of the simple food B also gets converted into a complex food H for storage purposes. This food gives blue-black colour with iodine solution?
(a) What is (i) organism A (ii) food B and food H?
(b) What are C and D?
(c) Name (i) green coloured substance E and organ F.
(d) What is the process G?
(a) (i) Organism A refers to Green plants.
(ii) Food B – Glucose
Food H – Starch

(b) C – Carbon dioxide
D – Water

(c) Green coloured substance E – Chlorophyll
Organ F – Leaves

(d) G – Photosynthesis process.

## Samacheer Kalvi 9th Science Guide Chapter 20 Organ Systems in Animals

Tamilnadu State Board New Syllabus Samacheer Kalvi 9th Science Guide Pdf Chapter 20 Organ Systems in Animals Text Book Back Questions and Answers, Notes.

## Tamilnadu Samacheer Kalvi 9th Science Solutions Chapter 20 Organ Systems in Animals

### 9th Science Guide Organ Systems in Animals Text Book Back Questions and Answers

I. Choose the correct answer :

Question 1.
Which of the following is not a salivary gland?
(a) Sublingual
(b) Lachrymal
(c) Submaxillary
(d) Parotid
(b) Lachrymal

Question 2.
Stomach of human beings mainly digests ……………….
(a) carbohydrates
(b) proteins
(c) fat
(d) sucrose
(b) proteins

Question 3.
To prevent the entry of food into the trachea, the opening is guarded by ………………..
(a) epiglottis
(b) glottis
(c) hard palate
(d) soft palate
(a) epiglottis

Question 4.
Bile helps in the digestion of ………………..
(a) proteins
(b) sugar
(c) fats
(d) carbohydrates
(c) fats

Question 5.
The structural and functional unit of the kidney is ………………..
(a) villi
(b) liver
(c) nephron
(d) ureter
(c) nephron

Question 6.
Which one of the following substance is not a constituent of sweat?
(a) Urea
(b) Protein
(c) Water
(d) Salt
(b) Protein

Question 7.
The common passage meant for transporting urine and sperms in male is ………………..
(a) ureter
(b) urethra
(c) vas deferens
(d) scrotum
(c) vas deferens

Question 8.
Which of the following is not a part of female reproductive system?
(a) Ovary
(b) Uterus
(c) Testes
(d) Fallopian tube
(c) Testes

II. Fill in the blanks :

1. The opening of the stomach into the intestine is called …………………
pylorus

2. The muscular and sensory organ which helps in mixing the food with saliva is ………………..
tongue

3. Bile, secreted by liver is stored temporarily in………………..

4. The longest part of alimentary canal is………………..
ileum

5. The human body functions normally at a temperature of about …………………
37°C

6. The largest cell in the human body of a female is………………..
ovum

III. State whether true or false. If false, correct the statement.

1. Nitric acid in the stomach kills microorganisms in the food.
False.
Correct statement : Hydrochloric acid in the stomach kills micro-organisms in the food.

2. During digestion, proteins are broken down into amino acids.
True.

3. Glomerular filtrate consists of many substances like amino acids, vitamins, hormones, salts, glucose and other essential substances.
False.
Correct statement: Hormones are not present in glomerular filtrate.

IV. Match the following :

 Organ Elimination 1. Skin (a) Urine 2. Lungs (b) Sweat 3. Intestine (c) Carbon dioxide 4. Kidneys (d) Undigested food

1 – b, 2 – c, 3 – d, 4 – a

V. Differentiate the following :

a. Excretion and Secretion
b. Absorption and Assimilation
c. Ingestion and Egestion
d. Diphyodont and Heterodont
e. Incisors and Canines
(a) Excretion
The process of removal of nitrogenous wastes generated in the body is called excretion.

Secretion
A process by which substances are produced and discharged from a cell, gland or organ for a function in the organism or for excretion.

(b)
Absorption
Absorption is the process by which nutrients obtained after digestion are absorbed by villi and circulated

1. throughout the body by blood and lymph and supplied to all body cells according to their requirements.
2. It takes place in the small intestine. It

Assimilation :

1. Assimilation means the incorporation of the absorbed food materials into the tissue cells as their internal and hoihogenous component.
2.  takes place in the cells of the body.

(c) Ingestion
The process of nutrition begins with intake of food, called ingestion.

Egestion :
The undigested or unassimilated portion of the ingested food material is thrown out from the body through the anal aperture as faecal matter. This is known as egestion or defaecation.

(d) Diphyodont
In human beings two sets of teeth (Diphyodont) are developed in their life time. The first appearing set of 20 teeth ca! led temporary or milk teeth are replaced by the second set of thirty two permanent teeth, sixteen in each jaw. This is called Diphyodont dentition.

Heterodont
Permanent teeth are of four types according to their struture and function namely Incisors, Canines, Premolars and molars. This is called Heterodont dentition.

(e) Incisors  :

1. Used for cutting and biting.
2. In a human adult there are 8 incisors

Canines

1. Used for tearing and piercing.
2. In a human adult there are 4 canines.

Question 1.
How is the small intestine designed to absorb digested food?
Small intestine comprises three parts- duodenum, jejunum and ileum. Ileum is the longest part of the small intestine. It contains minute finger-like projections called villi where absorption of food takes place. They are approximately 4 million in number. Internally, each villus contains fine blood capillaries and lacteal tubes.

Question 2.
Why do we sweat?
The human body functions normally at a temperature of about 37°C. When it gets hot sweat glands start secreting sweat, which contains water with small amounts of other chemicals like ammonia, urea, lactic acid and salts (mainly sodium chloride). The sweat passes through the pores in the skin and gets evaporated, which reduces the body temperature.

Question 3.
Mention any two vital functions of the human kidney.
Two vital functions of the kidneys are;

1. Maintain the fluid and electrolyte balance in our body.
2. Maintain the osmotic pressure in blood and tissues.

Question 4.
What is micturition?
When the urinary bladder is full the urine is expelled out through the urethra. This process is called micturition. A healthy person excretes one to two litres of urine per day.

Question 5.
Name the types of teeth present in an adult human being. Mention the functions of each.
Permanent teeth are of four types (Heterodont), according to their structure and function namely incisors, canines, premolars, and molars.

Types of teeth and their functions :

Question 6.
Explain the structure of nephron.

• Each kidney consists of more than one million nephrons. Nephrons or uriniferous tubules are structural and functional units of the kidneys.
• Each nephron consists of Renal corpuscle or Malphigian corpuscle and renal tubule.
• The renal corpuscle consists of a cup-shaped structure called Bowman’s capsule containing a bunch of capillaries called glomerulus.
• Blood enters the glomerular capillaries through afferent arterioles and leaves out through efferent arterioles.
• The Bowman’s capsule continues as the renal tubule which consists of three regions proximal convoluted tubule, U-shaped hair pin loop, the loop of Henle and the distal convoluted tubule.
• The distal convoluted tubule which opens into the collecting tubule. The nitrogenous wastes are drained into renal pelvis of kidney which leads to ureters and stored in the urinary bladder.
• Urine is expelled out through the urethra.

Question 1.
Describe the alimentary canal of man.
Alimentary canal is a muscular coiled, tubular structure. It consists of mouth, buccal cavity, pharynx, oesophagus, stomach, small intestine (consisting of duodenum, jejunum and ileum), large intestine (consisting of caecum, colon and rectum) and anus.

Mouth: Leads into the buccal cavity. It is bound 2 soft movable upper and lower lips. The buccal cavity is a large space-bound above by the palate (which separates the windpipe and food tube), below by the throat and on the sides by the jaws. The jaws bear teeth.

Teeth: Hard structures meant
for holding, cutting, grinding and crushing the food. In human beings, two sets of teeth (Diphyodont) are developed in their lifetime.

Each tooth has a root fitted in the gum (Theocodont). Permanent teeth are of four types (Heterodont), according to their structure and function namely incisors, canines, premolars and molars.

Dental formula represents the number of different type of teeth present in each half of a jaw (upper and lower jaw).
For Permanent teeth in each half of upper and lower jaw:
$$\frac{2,1,2,3}{2,1,2,3}$$ = 16 x 2 = 32

Salivary glands: There are 3 pairs

• Parotid glands Largest salivary glands, which lie in the cheeks in front of the ears.
• Sublingual glands Smallest lands and lie beneath the tongue.
• Submaxillary or Submandibular-glands-lie at the angles of the lower jaw.

Tongue: Muscular, sensory organ – Helps in mixing the food with the saliva.

Pharynx: It is a membrane-lined cavity behind the nose and mouth, connecting them to the oesophagus. Serves as” a pathway for the movement of food from mouth to oesophagus.

Oesophagus: Muscular-membranous canal about 22 cm in length. It conducts food ‘ from pharynx to the stomach by peristalsis (wave-like movement) produced by the rhythmic contraction and relaxation of the muscular walls of alimentary canal.

Stomach: Wide J-shaped muscular organ located.

Location: Between oesophagus and the small intestine.

Small intestine: The small intestine is the longest part of the alimentary canal, which is a long coiled tube measuring about 5 – 7 m. It comprises three parts- duodenum, jejunum, and ileum.

• Duodenum – C-shaped and receives the bile duct (from the liver) and pancreatic duct (from Pancreas). ’
• Jejunum Middle part of the small intestine. A short region of the small intestine.
• Ileum – Forms the lower part of the small intestine and opens into the large intestine.

Liver: Largest digestive gland of the body, reddish-brown in colour. Bile salts help in the digestion of fats by emulsification (conversion of large fat droplets into small ones).

Pancreas: Lobed, a leaf-shaped gland situated between the stomach and duodenum.
Pancreas acts both as an exocrine gland and as an endocrine gland.

Large intestine: The unabsorbed and undigested food is passed into the large intestine.
It extends from the ileum to the anus. About 1.5 meters in length. Has 3 parts colon and rectum.

Caecum: Small blind pouch-like structure at the junction of the small and large intestine.
From its blind end, a finger-like structure called a vermiform appendix arises. It is a vestigeal (functionless) organ in human beings.

Colon: Much broader than ileum. Passes up the abdomen on the right ascending colon,
crosses to the left just below the stomach (transverse colon) and down on the left side – (descending colon).

Rectum: Last part which opens into the anus muscles called mi;)! Spain opens when passing stools.

Question 2.
Explain the structure of the kidney and the steps involved in the formation of urine.
STRUCTURE OF KIDNEYS:

• Kidneys are bean-shaped reddish-brown in colour.
• The kidneys lie on either side of the vertebral column in the abdominal cavity attached to the dorsal body wall.
• The right kidney is placed lower than the left kidney as the liver takes up much space on the right side.
• Each kidney is about 11 cm long, 5 cm wide, and 3 cm thick.
• Internally the kidney consists of:
• An outer dark region the cortex. Longitudinal section of human kidney
• The inner lighter region the medulla.
• Both of these regions contain uriniferous tubules or nephrons.
• The medulla consists of multitubular conical masses called the
or whose bases are adjacent to the cortex.
• On the inner concave side of each kidney, a notch called hilum is present through which blood vessels and nerves enter in and the urine leaves out.

STEPS INVOLVED IN URINE FORMATION :

There are three stages.

1. Glomerular filtration
2. Tubular reabsorption and
3. Tubular secretion

Glomerular filtration: Urine formation begins with the filtration of blood through epithelial walls of the glomerulus and Bowman’s capsule. The filtrate is called the glomerular filtrate. Both essential and non-essential substances present in the blood are filtered.

Tubular reabsorption: The filtrate in the proximal tubule consists of essential substances such as glucose, amino acids, vitamins sodium-potassium bicarbonates, and water that are reabsorbed into the blood by a process of selective reabsorption

Tubular secretion: Substances such as EU or ions are secreted into the tubule. This tubular filtrate is finally known as urine , which is hypertonic in man Finally the urine passes into collecting ducts to the pelvis and through the ureter into the urinary bladder. When the urinary bladder is full the urine is expelled out through the urethra. This process is called micturition. The healthy person excretes 1-2 litres of urine/day.

VIII. Assertion and Reason :

Mark the correct answer as ;
a. If both Assertion and Reason are true and Reason is the correct explanation of Assertion.
b. If both Assertion and Reason are true but Reason is not the correct explanation of Assertion.
c. If Assertion is true but Reason is false.
d. If both Assertion and Reason are false.

Question 1.
Assertion: Urea is excreted out through the kidneys.
Reason: Urea is a toxic substance.
(a) Both Assertion and Reason are true and Reason is the correct explanation of Assertion

Question 2.
Assertion: In both the sexes gonads perform dual function.
Reason: Gonads are also called primary sex organs.
(a) Both Assertion and Reason are true and Reason is the correct explanation of Assertion

IX. Higher Order Thinking Skills :

Question 1.
If pepsin is lacking in gastric juice, then which event in the stomach will be affected?
a. digestion of starch into sugars.
b. breaking of proteins into peptides.
c. digestion of nucleic acids.
d. breaking of fats into glycerol and fatty acids.
b. breaking of proteins into peptides.

Question 2.
Name the blood vessel that
(a) enter malphigian capsule and
(b) leaves malphigian capsule.
(a) Afferent arteriole.
(b) Efferent arteriole.

Question 3.
Why do you think that urine analysis is an important part of medical diagnosis?
Urine is excreted from the human body which constitutes more than 95% water and other constituents like urea, chloride, sodium, potassium, creatinine and other dissolved ions, and inorganic and organic compounds. When there is an illness or disease, the constituents and its levels in urine also change.

Therefore urinalysis is also an important diagnostic tool which may be used to screen for and/or help diagnose conditions such as urinary tract infections, kidney disorders, liver problems, diabetes, or other metabolic conditions.

Question 4.
Drinking water helps

• Maintain the balance of fluids and electrolytes in the body.
• When muscle cells don’t get enough water it results in muscle fatigue.
• The functioning of kidneys also requires a lot of water.
• Staying hydrated is necessary for good health.

Question 5.
Can you guess why there are sweat glands on the palm of our hands and the soles of our feet?
Sweating is important for thermal regulation. Sweat works as a defense against microbes to which our hands and feet are mostly exposed than the other parts of our body.

X. Match the parts of the given figure with the correct option:

Intext Activities

ACTIVITY – 1

Look at the picture given below and answer the questions that follow :

1. Are the teeth of animals similar to ours?
2. How is the shape of their teeth related to their food habit?
There are many differences between human teeth and animal teeth.

• Humans have at most 32 teeth, but many animals have more than we do.
• Humans use them for breaking down food but animals need these teeth for breaking down of food and also for survival such as hunting, attacking, and defending themselves.

Lion Teeth: They are
Carnivore Teeth: Teeth are very sharp and scissor-like. Their front teeth are used to bite and hold onto prey while their long canine teeth are used for tearing flesh and meat. Their molars are also sharp – and used for slicing rather than chewing because they mainly swallow their food in whole chunks.

Bison or buffalo teeth: They are
Herbivore teeth: An herbivore is an animal that gets energy from eating plants. Herbivores have more molars than we do. They use these flat teeth for grinding branches, grasses, and seeds. Since their food doesn’t try to escape, they use their front teeth like pruning shears to clip leaves and stems.

### 9th Science Guide Organ Systems in Animals Additional Important Questions and Answers

I. Choose the correct answers :

Question 1.
In the dental formula $$\frac{2,1,2}{2,1,2}$$ 3 refers to ……………………
(a) incisors
(b) molars
(c) premolars
(d) canine
(b) molars

Question 2.
Lysozyme is seen in …………………….
(a) gastric juice
(b) intestinal juice
(c) bile
(d) saliva
(d) saliva

Question 3.
…………………… is the smallest gland.
(a) Pancreas
(b) Sublingual
(c) Parotid
(d) Submaxillary
(b) Sublingual

Question 4.
Curdling of milk protein is done by ……………………
(a) pepsin
(b) rennin
(c) lipase
(d) maltase
(b) rennin

Question 5.
……………………acts as birth canal.
(a) Fallopian tube
(b) Vagina
(c) Uterus
(d) Vasdeferens
(b) Vagina

Question 6.
The act of bringing swallowed food back to the mouth
(a) egestion
(b) ingestion
(c) micturition
(d) regurgitation
(d) regurgitation

Question 7.
Gastric glands do not secrete ……………………
(a) renin
(b) pepsin
(c) lipase
(d) none of the above
(c) lipase

Question 8.
Excretion means …………………….
(a) taking in oxygen from the air and giving out carbon dioxide.
(b) disposal of harmful germs and worms from our body.
(c) distribution of digested food to the body tissues through blood.
(d) removal of nitrogenous wastes generated in the body.
(d) removal of nitrogenous wastes generated in the body

Question 9.
Which is the major excretory product in human?
(a) H+ or K+
(b) Glucose
(c) Urea
(d) Creatinine
(a) H+ or K+

Question 10.
Which is a pear-shaped muscular organ in females?
(a) Uterus
(b) Fallopian tubes
(c) Ovaries
(d) Vagina
(a) Uterus

Question 11.
What is the other name of fallopian tubes?
(a) Ovaries
(b) Fimbriae
(c) Oviducts
(d) Ova
(c) Oviducts

II. Fill in the blanks :

1. ……………… is the smallest cell in males.
Sperm

2. Progesterone is secreted by………………
corpus luteum

3. The oviducts are also known as ………………
fallopian tubes

4. One mature ovum is released once in every……………… days.
28

5. Beta cells of pancreas produce ………………
insulin

6. Organs which are concerned with the formation, storage and elimination of urine constitute the ………………
excretory system

7. In the process of urine formation, the maximum amount of water from the glomerular filtrate is reabsorbed in the ………………
proximal convoluted tubule

8. ……………… receives the sperms, acts as birth canal during childbirth.
Vagina

9. The narrower lower part of the uterus is ………………
cervix

10. ……………… carries sperms to the seminal vesicles.
Vas deferens

11. ……………… is the smallest cell in the male body.
Sperm

12. The process of formation of sperms is known as ………………
spermatogenesis

13. ……………… is the vestigeal organ in human.
Vermiform appendix

14. ……………… acts as a thermoregulatory organ.
Sorotum

15. Tubular filtrate finally known as………………
urine

III. Match the following:

 Ovaries Bean shape Fallopian tubes Almond shape Uterus Funnel – shape Kidney Peas -shape

 Ovaries Bean shape Fallopian tubes Almond shape Uterus Funnel – shape Kidney Peas -shape

IV. Answer the following in one or two sentences :

1. It conducts food from pharynx to stomach by peristalsis.
Oesophagus.

2. Finger-like projections enhance the absorbing capacity of the small intestine.
Villi.

3. The bunch of capillaries inside the Bowman’s capsule.
Glomerulus.

4. Thin muscular tubes which carry urine from kidney to urinary bladder.
Ureter.

5. Small sac-like muscular structures that enclose testes.
Scrotal sacs.

V. Very short answer questions :

Question 1.
Name the salivary glands.
3 pairs of salivary glands are present in the mouth cavity.
They are Parotid glands, sublingual glands, and submaxillary or submandibular glands.

Question 2.
What is chyme?
The action of the gastric juice SSid churning of food in the stomach converts the bolus into a semi-digested food called chyme.

Question 3.
What are villi?
Ileum is the longest part of the small intestine. It contains minute finger-like projections called villi. They help in the absorption of food.

Question 4.
Name the bile salts.
Sodium glycolate and sodium tauraglycolate.

Question 5.
Name the bile pigments.
Bilirubin and Biliviridin

Question 6.
What is heparin?
It is an anticoagulant produced by the liver.

Question 7.
What are Islets of Langerhans?
The endocrine cells of the pancreas are known as Islets of Langerhans and they produced the hormones – insulin and glucagon.

Question 8.
What is succus entericus?
The intestinal glands secrete intestinal juice called succus entericus which contains enzymes like maltase, lactase, sucrase, lipase etc.

Question 9.
What is a vermiform appendix?
It is a finger-like structure originating from the blind end of the caecum, is the alimentary canal of man. It is a vestigial organ (functionless organ).

Question 10.
What is the contribution of Joseph E. Murray in Nephrology?
He performed the first successful kidney transplant operation.

Question 11.
What is parturition?
Childbirth is called parturition.

Question 1.
What is an artificial kidney?
Dialysis or artificial kidney :
(i) When kidneys lose their filtering efficiency, excessive amounts of fluid and toxic waste accumulate in the body. This condition is known as kidney (renal) failure.
For this, an artificial kidney is used to filter the blood of the patient. The patient is said to be put on dialysis and the process of purifying blood by an artificial kidney is called hemodialysis.
(ii) When renal failure cannot be treated by drug or dialysis, the patients are advised for kidney transplantation.

Question 2.
Draw the human excretory system and label the parts.

Question 3.
What are the end products of digestion of starch, proteins and fats respectively?
Starch – Glucose
Proteins – Amino acids
Fats – Fatty acids and glycerol

Question 4.
What are the functions of the ovaries and uterus in the female reproductive system?
Functions of ovaries :

• The ovaries are the female gonads, which produce ova or the female gametes.
• They also secrete the female sex hormones namely estrogen and progesterone.

Functions of the uterus :

• Uterus is a pear-shaped muscular, hollow structure present in the pelvic cavity.
• The development of foetus occurs inside the uterus.

Question 5.
Give reasons for the following
(a) Scrotum remains outside the body of human males.
(b) The wall of the stomach is not digested by its own enzyme.
(a) The two testes lie in the respective scrotal sacs. The scrotum acts as a thermoregulatory organ and provides an optimum temperature for the formation of sperms. The sperms develop at a temperature of 1-3°C lower than the normal body temperature. Hence scrotum remains outside the body of human males.

(b) The wall of the stomach is protected by mucus. Hence the wall of the stomach is not digested by its own enzymes. Further the gastric enzyme pepsinogen is present only in inactive form and converted into active pepsin only when food enters the stomach.

Question 6.
What is homeostasis?
The tendency of the body to seek and maintain a balance condition or equilibrium within its internal environment, even when faced with external challenges is called homeostasis.

Question 7.
Rearrange the jumbled sequence of the different parts of alimentary canal in proper sequence, (oesophagus, small intestine, stomach, large intestine, anus, mouth, rectum)
Mouth, oesophagus, stomach, small intestine, large intestine, rectum, anus.

Question 8.
Select the substances given below that need to be excreted from the body, (urea, amino acids, carbon dioxide, uric acid, glucose)
Urea and carbon dioxide

Question 9.
Rearrange the jumbled words and fill in the blanks in the following passage to make it a meaningful description.
The human urinary system consists of a pair of …….. ( nyedik), which form the urine; a pair of …….. (ertreu), which conduct the …….. (neuri) from kidneys to the …….. (naryuri drebdal) for storage of urine and a …….. (reuhrat) through which the urine is voided by bladder contractions.
1. Kidney
2. Ureter
3. Urine
5. Urethra

Question 1.
List the function of the liver.

• Synthesizes foetal red blood cells.
• Produces fibrinogen and prothrombin, used for clotting of blood.
• Destroys red blood cells.
• Stores iron, copper, vitamins A, and D.
• Produces heparin (an anticoagulant).
• Excretes toxic and metallic poisons.
• Detoxifies substances including drugs and alcohol.

Question 2.
Draw a chart to show the various enzymes produced during digestion in our body and their action.

Question 3.
Write a note on teeth of humans.

• Teeth are hard structures meant for holding, cutting, grinding, and crushing the food.
• In human beings, two sets of teeth (Diphyodont) are developed in their lifetime. The first appearing set of 20 teeth called temporary or milk teeth are replaced by the second set of thirty-two permanent teeth, sixteen in each jaw. Each tooth has a root fitted in the gum (Theocodont).
• Permanent teeth are of four types (Heterodont), according to their structure and function namely incisors, canines, premolars, and molars.
• Dental formula represents the number of different types of teeth present in each half of a jaw (upper and lower jaw).
• The types of teeth are denoted as incisors (i), canine (c), premolars (pm) and molars (m). The dental formula is presented as:

For Milk teeth in each half of upper and lower jaw:
$$\frac{2,1,2}{2,1,2}$$= 10 x 2 = 20
For Permanent teeth in each half of upper and lower jaw:

$$\frac{2,1,2,3}{2,1,2,3}$$ = 16 x 2 = 32
Types of teeth and their functions

Question 4.
Write a note on functions of liver in digestion.

• It is the largest digestive gland of the body which is reddish-brown in colour.
• It is divided into two main lobes, right and left lobes. The right lobe is larger than the left lobe.
• On the undersurface of the liver, gall bladder is present. The liver cells secrete bile which is temporarily stored in the gall bladder.
• Bile is released into small intestine when food enters in it. It has bile salts (sodium glycolate and sodium tauraglycolate) and bile pigments (bilirubin and biliviridin).
• Bile ssfits help in the digestion of fats by bringing about their emulsification (conversion of large fat droplets into small ones).

Question 5.
Write a note on the skin.

• Skin is the outermost covering of the body. It stretches all over the body in the form of a layer.
• It accounts for 15% of an adult’s human body weight. There are many structures and glands derived from the skin. It eliminates metabolic wastes through perspiration.
• The human body functions normally at a temperature of about 37 C.
• When it gets hot sweat glands to start secreting sweat, which contains water with small amounts of other chemicals like ammonia, urea, lactic acid and salts (mainly sodium chloride).
• The sweat passes through the pores in the skin and gets evaporated.

VIII. Higher Order Thinking Skills :

Question 1.
Reproductive organs are also considered endocrine glands.