The main nitrogenous waste of Hydra is

Options

A. Ammonia
B. Urea
C. Uric acid
D. Both A and C.

Answer

To solve the question regarding the main nitrogenous waste of Hydra, we can follow these steps:

### Step-by-Step Solution:

1. **Identify the Organism**:
- The question asks about Hydra, which is a freshwater invertebrate.

2. **Understand the Classification**:
- Hydra belongs to the phylum Cnidaria (also known as Coelenterata).

3. **Determine the Excretion Method**:
- Hydra, being an aquatic organism, excretes nitrogenous waste through diffusion.

4. **Identify the Type of Nitrogenous Waste**:
- The primary nitrogenous waste produced by aquatic organisms, including Hydra, is ammonia. This is because ammonia is highly soluble in water and can be easily excreted by organisms living in aquatic environments.

5. **Consider Other Nitrogenous Wastes**:
- Urea and uric acid are forms of nitrogenous waste typically found in terrestrial organisms. Urea is excreted by mammals, while uric acid is found in reptiles and birds.

6. **Conclusion**:
- Since Hydra excretes ammonia as its main nitrogenous waste, the correct answer to the question is ammonia.

### Final Answer:
The main nitrogenous waste of Hydra is **ammonia**.

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