Question

Ciliary muscles are contractile structures which

• A. Move cilia of some protozoans
• B. Keep valves of heart intact
• C. Change focal length of human eye and are found at junction of sclera and iris
• D. Cause erection of human hairs in cold and are situated in skin

Answer 1

The correct option is C Change focal length of human eye and are found at junction of sclera and iris

The ciliary muscle is a circular muscle that relaxes or tightens the zonules to enable the lens to change shape for focusing. It is present between the sclera (white of the eye) and the fine ligaments, that suspend the lens. It is composed of both longitudinal and circular fibres and serves to change the shape of the lens, enabling the eye to focus on near or distant objects.
Thus, the correct answer is option C.