Which of the following organisms is nonparasitic ?

Options

A. Hydra
B. Taenia
C. Hirudinaria
D. Anopheles

Answer

To determine which of the following organisms is nonparasitic, we can analyze the characteristics of each option provided.

### Step-by-Step Solution:

1. **Understand the Definition of Parasitic Organisms**:
- Parasitic organisms are those that depend on a host for their survival, nutrition, and reproduction. They usually harm the host in the process.

2. **Examine the Organisms**:
- **Hydra**: This is a simple aquatic organism that can live independently in water. It does not depend on any host for its nutrition or life cycle. Therefore, it is classified as nonparasitic.
- **Tenia (Tapeworm)**: This is a well-known parasite that lives in the intestines of its host (usually humans or other animals) and absorbs nutrients from the host's digested food.
- **Herodineria (Leech)**: While some leeches can be free-living, many are parasitic and feed on the blood of their hosts.
- **Anopheles (Mosquito)**: This is a genus of mosquitoes that can be parasitic, as they feed on the blood of their hosts (humans and other animals) and can transmit diseases like malaria.

3. **Identify the Nonparasitic Organism**:
- Based on the analysis, Hydra is the only organism that does not rely on a host for survival and is therefore nonparasitic.

4. **Conclusion**:
- The correct answer to the question "Which of the following organisms is nonparasitic?" is **Hydra**.