C. Pupil Reflex

Pupil reflex refers to the changes in size of the pupil when exposed to light of different intensities.

In Bright Light,

• Circular muscles of the iris contract.

• Radial muscles of the iris relax.

• Pupil becomes smaller in size or constricts to reduce the amount of light entering the eye.

In Dim Light,

• Radial muscles of the iris contract.

• Circular muscles of the iris relax.

• Pupil becomes larger in size or dilates to increase the amount of light entering the eye.

Through pupil reflex, the pupil changes in size to reduce the fluctuations in the amount of light entering the eye. This serves as the eye's adaptations to bright and dim conditions.