Parapodia for locomotion are found in one of the following .

Options

A. Earthworm
B. Hirudinaria
C. Nereis
D. Polygordius

Answer

**Step-by-Step Solution:**

1. **Identify the Question**: The question asks which organism has parapodia for locomotion.

2. **Understand Parapodia**: Parapodia are lateral extensions found on the segments of certain annelids, primarily used for locomotion.

3. **Review the Options**: The options provided are:
- Earthworm
- Herodinaria (Leech)
- Nereus
- Polygordias

4. **Analyze Each Option**:
- **Earthworm**: Earthworms belong to the class Oligochaeta and do not possess parapodia. They move using a different mechanism involving contraction of muscles and bristles (setae).
- **Herodinaria (Leech)**: Leeches are also part of the class Hirudinea and do not have parapodia. They use suckers for movement.
- **Nereus**: Nereus is a marine polychaete annelid. It is characterized by a metamerically segmented body, with each segment bearing parapodia, which are used for locomotion.
- **Polygordias**: Polygordias is another type of polychaete, but it is less commonly referenced in terms of locomotion compared to Nereus.

5. **Conclusion**: Based on the analysis, the organism that has parapodia for locomotion is **Nereus**.

6. **Final Answer**: The correct answer is **Nereus** (Option 3).

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