Which is correct about earthworm ?

Options

A. It can crawl on smooth surface easily
B. It secretes cocoon around unfertilized eggs
C. It has brain but not head
D. It has no locomotory organs.

Answer

### Step-by-Step Solution

1. **Identify the Organism**: The question is about the earthworm, a terrestrial invertebrate that lives in moist soil.

2. **Understand the Anatomy**: The anterior end of the earthworm contains the mouth and a structure called the prostomium. The prostomium serves two main functions: it covers the mouth and acts as a wedge to help the earthworm burrow into the soil.

3. **Evaluate the Statements**:
- **Statement 1**: "It can crawl on smooth surfaces easily."
- **Analysis**: This statement is incorrect. Earthworms are adapted to live in soil and find it difficult to move on smooth surfaces due to their body structure.

- **Statement 2**: "It secretes a cocoon around the unfertilized egg."
- **Analysis**: This statement is also incorrect. Earthworms secrete a cocoon around fertilized eggs, not unfertilized ones.

- **Statement 3**: "It has a brain but not a head."
- **Analysis**: This statement is correct. Earthworms have a simple nervous system with a brain, but they do not have a distinct head like many other animals.

- **Statement 4**: "It has no locomotory organs."
- **Analysis**: This statement is incorrect. Earthworms have setae, which are bristle-like structures that help them move through the soil.

4. **Conclusion**: After evaluating all the statements, the only correct statement about the earthworm is that it has a brain but not a head.

### Final Answer
The correct statement about the earthworm is: **It has a brain but not a head.**

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