Question

Which of the following controls the size of the pupil?

• A. Eye lens
• B. Retina
• C. Iris
• D. Ciliary muscles

Hint:

The iris acts like the diaphragm of a camera, controlling the amount of light that enters the eye.

Answer 1

The Correct Option is C

Step 1: Role of Pupil and Iris:
The pupil is the small opening in the center of the eye that regulates the amount of light entering the eye. Its size is controlled by the iris, which is the coloured part of the eye. Step 2: Function of Iris:
In bright light → Iris contracts the pupil to reduce light entry.
In dim light → Iris dilates the pupil to allow more light.
Step 3: Analysis of Options:
Eye lens: Helps in focusing light, not controlling pupil size.
Retina: Converts light into nerve impulses.
Ciliary muscles: Change lens curvature, not pupil size.
Iris: Controls pupil size. (Correct)
Step 4: Final Answer:
The Iris controls the size of the pupil.