Ncert Solutions Class 6 Science Chapter 8 Body Movements

Page No 77:

Question 1:

Fill in the blanks:
(a) Joints of bones help in the _________ of body.
(b) A combination of bones and cartilages forms the _________ of the body.
(c) Bones at the elbow are joined by a _________ joint.
(d) The contraction of the _________ pulls the bones during movement.

Answer:

(a) Joints of bones help in the __movement__ of body.
(b) A combination of bones and cartilages forms the __skeleton__ of the body.
(c) Bones at the elbow are joined by a __hinge__ joint.
(d) The contraction of the __muscle__ pulls the bones during movement.

Question 2:

Indicate true (T) or false (F) for the following sentences.
(a) Movement and locomotion of all animals is exactly the same. ( )
(b) Cartilages are harder than bones. ( )
(c) Finger bones do not have joints. ( )
(d) The fore arm has two bones. ( )
(e) Cockroaches have an outer skeleton. ( )

Answer:

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

Page No 78:

Question 3:

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

Column I	Column II
Upper jaw	have fins on the body
Fishes	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
Fishes	have a streamlined body; have fins on the body
Ribs	protect the heart
Snail	shows very slow movement
Cockroach	has an outer skeleton; can fly in the air

Question 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) Ball and socket joint is a movable joint. It consists of a bone that has a round head, which fits into a cup like depression of another bone. This helps the bone to rotate freely. Examples of such joints are hip and shoulder joints.
(b) Mandible bone which forms the lower jaw is the only skull bone that is movable.
(c) The elbow has a hinge joint. This type of a joint allows the movement in one plane only. Therefore, our elbow cannot move backwards.