The visual unit of cockroach are

Options

A. Ocelli
B. Ctenidia
C. Ommatidia
D. Rhabdoma

Explanation

To answer the question "The visual unit of cockroach are," we need to identify the correct term that describes the components of the compound eyes of a cockroach.

### Step-by-step Solution:

1. **Understanding the Structure of Cockroach Eyes**:
- Cockroaches possess compound eyes, which are made up of multiple units that work together to form a single image.

2. **Identifying the Components**:
- The visual units of compound eyes are called ommatidia. Each ommatidium is a small, hexagonal structure that contributes to the overall vision of the cockroach.

3. **Counting the Ommatidia**:
- A single compound eye in a cockroach can contain approximately 2000 ommatidia. This large number allows the cockroach to have a wide field of vision.

4. **Function of Ommatidia**:
- The ommatidia work together to provide the cockroach with a mosaic vision, which means that the cockroach sees multiple images of an object simultaneously.

5. **Conclusion**:
- Based on the information gathered, the correct answer to the question is that the visual units of the cockroach are **ometidia**.

### Final Answer:
The visual unit of cockroach are **ometidia**.