Answer:
Iris
Explanation:
Iris can be described as a part of the eyes which regulates the amount of light that enters the eye. The iris is made up of various muscles that control the size of the pupil
When a person is in a well-lighted room, the iris decreases the size of the pupil so that a low amount or medium amount of light is absorbed into the pupil. Also when an individual steps into a dark room the iris increases the size of the pupil so that a high amount of light penetrates the pupil.
Hence without the iris the amount of light that enters the eye cannot be controlled.
