Question

Define backbone, Ball and socket joint and bristles

Answer 1

Dear Student,

The human backbone is made up of 33 smaller bones known as vertebrae. Between any two vertebrae is the spinal disc that cushions movements between the vertebrae. The vertebrae near the top of the backbone are the smallest and the ones at the bottom are the largest. Each vertebra has horn like projections where muscles attach and allow movement of the spine.
Each vertebra also has a passage through it. The spinal cord passes through this passage.

Ball and socket joint is the joint which is present in shoulders and hips and is meant for movement of limbs in all directions. Round end of bone fits into the cavity of the other bone can move in all directions in a circle. Shoulder joint is also ball and socket joint.

Bristles are stiff hair present on animal's skin.
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