Gas exchange surface of Earthworm is

Options

A. Skin
B. Gills
C. Ctenidia
D. Trachea

Answer

**Step-by-Step Solution:**

1. **Identify the Organism**: The question asks about the gas exchange surface of an earthworm. Earthworms belong to the phylum Annelida.

2. **Understand the Gas Exchange Process**: In earthworms, gas exchange is crucial for survival. They need to take in oxygen and expel carbon dioxide.

3. **Recognize the Lack of Specialized Organs**: Earthworms do not have specialized respiratory organs like lungs or gills. Instead, they rely on a different method for gas exchange.

4. **Identify the Gas Exchange Surface**: The gas exchange in earthworms occurs through their skin. Oxygen diffuses into the body, and carbon dioxide diffuses out through the skin.

5. **Conclusion**: Therefore, the gas exchange surface of an earthworm is its skin.

**Final Answer**: The gas exchange surface of an earthworm is the skin.

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