Parapodia are locomotary structure in

Options

A. Scolopendra
B. Nereis
C. Centipede
D. Earth worm

Answer

**Step-by-Step Solution:**

1. **Understanding Parapodia**: Parapodia are lateral extensions found in certain organisms that serve as locomotory structures. They are typically fleshy and are used for movement in aquatic environments.

2. **Identifying the Organisms**: The question asks which organism has parapodia as locomotory structures. The options provided are Scolopendra, Nereus, Centipede, and Earthworm.

3. **Analyzing Each Option**:
- **Scolopendra**: This organism is a type of centipede and has pencil-like appendages known as forcipules, not parapodia. Therefore, this option is incorrect.
- **Nereus**: This is a genus of polychaete worms, which are known to possess parapodia. These structures help in locomotion. Hence, this option is correct.
- **Centipede**: Centipedes belong to the phylum Arthropoda and have jointed appendages, not parapodia. Thus, this option is also incorrect.
- **Earthworm**: Earthworms do not have parapodia; they have a different structure for movement. Therefore, this option is incorrect as well.

4. **Conclusion**: After analyzing all the options, the correct answer is **Nereus**, as it is the only organism listed that has parapodia functioning as locomotory structures.

**Final Answer**: Parapodia are locomotory structures in **Nereus**.

---