NCERT Solutions for Class 6th: Ch 8 Body Movements Science

NCERT Solutions for Class 6th: Ch 8 Body Movements Science

Page No: 77

Exercises

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.

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.

2. 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) False
(b) False
(c) False
(d) True
(e) True

Page No. 78

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

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.

Answer

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	shows very slow movement.
Cockroach	has an outer skeleton, 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?

Answer

(a) In a ball and socket joint, the rounded end of one bone fits into the cavity (hollow space) of the other bone. It can allows movement in all directions.
(b) Lower jaw bone (Mandible bone) is the only movable bone in skull bone.
(c) Elbow joint has hinge joint. This joint allows movement in a plane only and hence it is not able to move backwards.

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