Question

(1) Cockroach
(c) can fly in the air, and (b) has an outer
skeleton
4. Answer the following questions:
(a) What is a ball and socket joint?
(b) Which of the skull bones are movable?
(d Why can our elbow not move backwards?
(a) The rounded end of one bone fits into the hollow space of other bone. This is
called ball and socket joint, Ball and socket joints allow movements in all the
directions, e.g. shoulder and hip can be moved in all directions.
(b) In skull, only lower jaw is movable.
(d Our elbow cannot move backwards because the elbow has a hinge joint that
allows movement in only one direction.
BODY MOVEMENTS
101​

Answer 1

Answer:

(a) A joint in which the rounded end of one bone fits into the hollow space of other bone is called ball and socket joint. ... All the other bones of skull are immovable. (c) Our elbow cannot move backwards because the elbow has a hinge joint that allows movement in only one direction.