Which part of the eye is a muscle that regulates the size of the pupil?
A) iris
B) lens
C) retina
D) sclera

Question

Which part of the eye is a muscle that regulates the size of the pupil?
A) iris 
B) lens 
C) retina
D) sclera

Quizplus · Accepted Answer

The iris is the muscular part of the eye that controls the size of the pupil, which regulates the amount of light that enters the eye. The lens focuses the light onto the retina, which contains the light-sensitive cells that send signals to the brain, and the sclera is the tough outer layer that protects the eye.

Which Part of the Eye Is a Muscle That Regulates