NCERT Solutions For Class 6 Science Chapter 8 Exercise

NCERT Solutions For Class 6 Science Chapter 8 Exercise

Chapter 8: Body Movements

1. Fill in the blanks.

(a) Joints of the bones help in the ——————— of the body.

(b) A combination of bones and cartilages forms the _______ of the body.

(c) The bones at the elbow are joined by a ______________________ joint.

(d) The contraction of the _____________ pulls the bones during movement.

Solution:

(a) Joints of the bones help in the movement of the body.

(b) A combination of bones and cartilages forms the skeleton of the body.

(c) The bones at the elbow are joined by a hinge joint.

(d) The contraction of the muscles pulls the bones during movement.

2. Indicate true (T) and false (F) among the following sentences.

(a) The movement and locomotion of all animals are exactly the same. ( )

(b) The cartilages are harder than bones. ( )

(c) The finger bones do not have joints. ( )

(d) The forearm has two bones. ( )

(e) Cockroaches have an outer skeleton. ( )

Solution:

a) False

b) False

c) False

d) True

e) True

3. Match the items in Column I with one or more items of Column II.

Solution:

Column I	Column II
Upper jaw	Have fins on the body
Fish	Has an outer skeleton
Ribs	Can fly in the air
Snail	Is an immovable joint
Cockroach	Protect the heart
	Shows very slow movement
	Have a streamlined body

Solution:

Column I	Column II
Upper jaw	Is an immovable joint
Fish	Have fins on the body, have a streamlined body
Ribs	Protect the heart
Snail	Has an outer skeleton and Shows very slow movement
Cockroach	Has an outer skeleton and Can fly in the air

4. Answer the following.

(a) What is a ball and socket joint?

(b) Which of the skull bones are movable?

(c) Why can our elbow not move backwards?

Solution:

a) The rounded end of one bone fits into the cavity (hollow space) of the other bone. Such a joint allows movements in all directions, which is called a ball and socket joint.

b) Lower jaw

c) Our elbow cannot move backwards because it has hinge joints which only allow back-and forth-movement.

 

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