Question

Which of the following best describes the function of the iris?

A) Gives the eye its color
B) Controls the amount of light entering the eye
C) Adjusts the shape of the lens
D) Refracts light through the pupil

Answer 1

The primary function of the iris is to control the amount of light entering the eye by adjusting the size of the pupil.

Step-by-step explanation:

The function of the iris is to control the amount of light entering the eye. It does this by altering the size of the pupil: it causes the pupil to narrow in bright light to reduce the amount of light that can enter, and it causes the pupil to widen in dim light to allow more light to enter. While the iris does give the eye its color, its primary role is in regulating light entry, which is crucial for vision.