What is the function of the iris in human eye?

Explanation

### Step-by-Step Solution:

1. **Understanding the Structure of the Eye**: The human eye consists of various parts, including the lens, ciliary muscles, iris, pupil, and retina. The iris is the colored part of the eye surrounding the pupil.

2. **Identifying the Iris**: The iris is the part of the eye that gives it color, which can vary from person to person (e.g., blue, brown, green). This color is due to the pigmentation in the iris.

3. **Main Function of the Iris**: The primary function of the iris is to control the size of the pupil. The pupil is the opening in the center of the iris through which light enters the eye.

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