Which of the following have eye structure nearest to that of vertebrates?

Options

A. insecta
B. polychaeta
C. cephalopoda
D. crustacea

Answer

To determine which of the following groups has an eye structure nearest to that of vertebrates, we will analyze the options provided: Insecta, Polychaeta, Cephalopoda, and Crustacea.

### Step-by-Step Solution:

1. **Understand the Eye Structure of Vertebrates**:
- Vertebrates possess a well-defined eye structure that is housed within an eyeball or orbit. This structure allows for complex vision and is a characteristic feature of vertebrate anatomy.

2. **Examine Each Group**:
- **Insecta**: Insects have compound eyes, which are made up of many small visual units called ommatidia. This structure is quite different from the single lens eye of vertebrates.
- **Polychaeta**: These are segmented worms that may have simple eyes (ocelli) but do not have a complex eye structure similar to vertebrates.
- **Cephalopoda**: This class includes squids, octopuses, and nautiluses. They possess a camera-like eye structure that is remarkably similar to that of vertebrates, with a lens, retina, and iris.
- **Crustacea**: Crustaceans typically have compound eyes similar to insects, which do not resemble the vertebrate eye structure.

3. **Identify the Closest Match**:
- After analyzing the eye structures of each group, it is clear that **Cephalopoda** has the eye structure that is nearest to that of vertebrates. Their eyes are more complex and share similarities in terms of structure and function.

4. **Conclusion**:
- Therefore, the correct answer to the question is **Cephalopoda**.