Earthworm respires by:-

Options

A. Clitellum
B. Ctenidia
C. Moist skin
D. Typhlosole

Answer

**Step-by-Step Solution:**

1. **Understanding Earthworm Respiration**: Earthworms primarily respire through their skin. They require a moist environment for gas exchange to occur effectively.

2. **Analyzing the Options**:
- **Clitellum**: This is a thickened, glandular section of the earthworm that plays a role in reproduction (copulation) but is not involved in respiration.
- **Tinnidia**: This is a respiratory structure found in some mollusks and insects, not in earthworms.
- **Moist Skin**: Earthworms have a moist skin surface that allows for the diffusion of gases (oxygen and carbon dioxide) directly through the skin into the bloodstream.
- **Typhlosol**: This structure is part of the digestive system in earthworms, increasing the surface area for absorption and digestion, but it does not play a role in respiration.

3. **Conclusion**: The correct answer is that earthworms respire through their moist skin, which facilitates gas exchange.

**Final Answer**: Earthworm respires by moist skin.

---