Ammonia is the main nitrogenous excretory material in

Options

A. Amphibians
B. Aves
C. Tadpoles
D. Reptiles

Answer

### Step-by-Step Solution:

1. **Understanding Nitrogenous Excretion**:
- Nitrogenous waste is a byproduct of protein metabolism in organisms. Different organisms excrete nitrogenous waste in various forms, including ammonia, urea, and uric acid.

2. **Identifying Ammonia as an Excretory Product**:
- Ammonia is a highly toxic compound and is primarily excreted by aquatic organisms. It is soluble in water, which allows these organisms to easily eliminate it from their bodies.

3. **Defining Aminotelism**:
- The process of excreting ammonia is known as aminotelism. Organisms that primarily excrete ammonia are referred to as aminotelic organisms.

4. **Identifying Aminotelic Organisms**:
- Common examples of aminotelic organisms include many aquatic animals, particularly fish, and the larval stages of amphibians, such as tadpoles.

5. **Conclusion**:
- Given the question, "Ammonia is the main nitrogenous excretory material in," the correct answer is **tadpoles**, as they are aquatic and excrete ammonia efficiently due to its solubility in water.

### Final Answer:
Ammonia is the main nitrogenous excretory material in **tadpoles**.

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