AP PSYCHOLOGY

Detailed explanation-1: -The size of the pupil is controlled by Iris. Iris contains a group of two smooth muscles attached at the corner of the pupil. They stretch when there is less light and shrink when it is too bright. These muscles are known as sphincter pupillae.

Detailed explanation-2: -The size of the pupil is controlled by the activities of two muscles: the circumferential sphincter muscle found in the margin of the iris, innervated by the parasympathetic nervous system: and the iris dilator muscle, running radially from the iris root to the peripheral border of the sphincter.

Detailed explanation-3: -Iris muscles are the two sheets of muscles in the iris with contrary actions i.e., dilation and contraction. These muscles are known for controlling the size of the pupil and thereby determining the amount of light that is reaching the sensory tissue of the retina.