What is the function of iris in human eye?

Options

A. To control or regulate the amount of coming light to the eye
B. To return the coming light to the eye
C. to send the photo to the image lens
D. None of the above

Explanation

### Step-by-Step Solution:

1. **Understanding the Structure of the Eye**: The human eye consists of several parts, including the cornea, lens, retina, and iris. Each part has a specific function that contributes to vision.

2. **Identifying the Iris**: The iris is the colored part of the eye that surrounds the pupil. It is a thin, circular structure that plays a crucial role in regulating light entry.

3. **Function of the Iris**: The primary function of the iris is to control the size of the pupil. This regulation helps to manage the amount of light that enters the eye.

4. **Mechanism of Action**: When there is bright light, the iris constricts (makes the pupil smaller) to reduce the amount of light entering the eye, protecting the retina from excessive brightness. Conversely, in dim light, the iris dilates (makes the pupil larger) to allow more light to enter, improving visibility.

5. **Conclusion**: Therefore, the function of the iris in the human eye is to control and regulate the amount of light that comes into the eye, ensuring optimal vision and protecting the eye from damage.

### Final Answer:
The function of the iris in the human eye is to control and regulate the amount of light that enters the eye.

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