In a copulatory pair of earthwonns, there occur

Options

A. Reciprocal fertilization and internal fertilization
B. Cross fertilization and external fertilization
C. External fertilization and internal fertilization
D. Cross fertilization and reciprocal fertilization

Answer

To answer the question regarding what occurs in a copulatory pair of earthworms, we can break down the information step by step:

### Step-by-Step Solution:

1. **Understanding Earthworm Reproduction**:
- Earthworms are hermaphrodites, meaning each individual possesses both male and female reproductive organs.

2. **Copulation Process**:
- During copulation, two earthworms align themselves ventrally and secrete mucus from their clitellum, which helps them stick together temporarily.

3. **Sperm Exchange**:
- While they are joined, each earthworm transfers sperm to the other. This process is known as cross-fertilization because each worm contributes sperm to the other.

4. **Fertilization Type**:
- The fertilization that occurs is internal. The sperm is stored in a special sac (spermatheca) within the receiving earthworm until the eggs are ready to be fertilized.

5. **Conclusion**:
- Therefore, in a copulatory pair of earthworms, both reciprocal fertilization (exchange of sperm) and internal fertilization (fertilization of eggs inside the body) occur.

### Final Answer:
The correct option is: **Reciprocal fertilization and internal fertilization.**

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