NCERT Solutions for Class 6 Science Chapter 8 Body Movements

Q1 ) 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.

Answer :

(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.

Q2 ) Indicate true (T) and false (F) among the following sentences.

(a) The movement and locomotion of all animals is exactly the same. ( )
(b) The cartilages are harder than bones. ( )
(c) The finger bones do not have joints. ( )
(d) The fore arm has two bones. ( )
(e) Cockroaches have an outer skeleton. ( )

Answer :

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

REASON : The movement and locomotion of different animals is different.


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

REASON : Cartilages are not as hard as bones and can be bent easily.


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

REASON : The finger bones have joint.


(d) The fore arm has two bones. ( T)


(e) Cockroaches have an outer skeleton. ( T)

Q3 ) Match the items in Column I with one or more items of Column II.

Column I

Upper jaw
Fish
Ribs
Snail
Cockroach

Column II

Have fins on the body
Has an outer skeleton
Can fly in the air
is an immovable joint
Protect the heart
Shows very slow movement
Have a streamlined body

Answer :

Column I \(\space\) \(\rightarrow \) \(\space\) Column II


Upper jaw \(\rightarrow \) Is an immovable joint

Fish \(\rightarrow \) Have fins on the body ; Have a streamlined body

Ribs \(\rightarrow \) Potect the heart

Snail \(\rightarrow \) Shows very slow movement ; Has an outer skeleton

Cockroach \(\rightarrow \) Has an outer skeleton ; Can fly in air

Q4 ) 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?

Answer :

(a) Ball and socket joint is a movable joint. In this, a bone with a round head fits into the hollow space of another bone.
This makes the bone to rotate freely. For example, bones of the hip and shoulder can move in all directions due to ball and socket joints.

(b) The lower jaw bone of the skull is the only movable bone. It allows us to chew food and talk. It is known as mandible.

(c) Our elbow cannot move backwards because it has hinge joints that only allow back and forth movement and movement in one plane only.