Question

part of the eye that regulates the amount of light entering the eye

Answer 1

The iris is the ring of pigmented tissue surrounding the pupil that varies in color. The iris opens and closes to control the amount of light entering the eye through the pupil. The pupil is the opening in the center of the iris where light enters the eye.

Answer 2

The iris with the help of
pupil is the part of the eye that controls the amount of light entering the eye.
Hope it helps dear........