Bacteria present in the body surface of earthworm are destroyed by:-

Options

A. Excretory substance secreted by nephyridia
B. By Coelomic fluid
C. By antibodies
D. By Saliva

Answer

To determine how bacteria present on the body surface of earthworms are destroyed, we can follow these steps:

### Step-by-Step Solution:

1. **Identify the Context**: Understand that earthworms have bacteria on their body surface that need to be destroyed for their health.

2. **Explore the Options**: The options provided for the destruction of bacteria include:
- Nephridia secreted Extraterrestrial Substance
- Coelomic Fluid
- Antibodies
- Saliva

3. **Understand Coelomic Fluid**: Coelomic fluid is a fluid found within the coelom (body cavity) of earthworms. It contains various cells that play a role in immunity.

4. **Identify Key Cells in Coelomic Fluid**:
- **Phagocytes**: These cells engulf and destroy bacteria.
- **Mucocytes**: These cells secrete mucus, which can trap bacteria.
- **Circular and Chloragogen Cells**: These cells are involved in various metabolic processes and can also play a role in immune response.
- **Amebocytes**: These are numerous and function similarly to phagocytes, actively participating in the destruction of bacteria.

5. **Conclusion**: Given that coelomic fluid contains phagocytes and amebocytes that actively destroy bacteria, we conclude that the bacteria present on the body surface of earthworms are primarily destroyed by the coelomic fluid.

### Final Answer:
Bacteria present in the body surface of earthworm are destroyed by **coelomic fluid**.

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