The size of pupil is controlled by the

Options

A. Conjunctiva
B. Cornea
C. Iris
D. Retina.

Answer

**Step-by-Step Solution:**

1. **Understanding the Question**: The question asks about what controls the size of the pupil in the eye.

2. **Identifying the Options**: The options provided are conjunctiva, cornea, iris, and retina.

3. **Analyzing Each Option**:
- **Conjunctiva**: This is a membrane that covers the front of the eye and lines the inside of the eyelids. It does not control the size of the pupil.
- **Cornea**: This is the transparent front part of the eye that covers the iris and pupil. It helps focus light but does not control pupil size.
- **Iris**: This is the colored part of the eye that surrounds the pupil. It contains muscles that control the size of the pupil.
- **Retina**: This is the layer at the back of the eye that detects light and sends signals to the brain. It does not control the pupil size.

4. **Conclusion**: The size of the pupil is controlled by the **iris**, which contains two types of muscles:
- **Circular muscles**: These contract in bright light, making the pupil smaller.
- **Radial muscles**: These contract in dark light, making the pupil larger.

5. **Final Answer**: Therefore, the correct answer is **iris** (Option 3).

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