Shifting of ammonotelism to ureotelism is seen in

Options

A. Frog
B. Fishes
C. Birds
D. Man

Answer

To solve the question regarding the shifting of ammonotelism to ureotelism, we can follow these steps:

### Step-by-Step Solution:

1. **Understand Ammonotelism and Ureotelism**:
- Ammonotelism is the process by which organisms excrete ammonia as their primary nitrogenous waste. This is common in aquatic animals, as ammonia is highly soluble in water and can be easily diluted.
- Ureotelism is the process where organisms excrete urea instead of ammonia. Urea is less toxic and requires less water for excretion, making it more suitable for terrestrial organisms.

2. **Identify Organisms**:
- The question presents four options: frogs, fishes, birds, and humans. We need to analyze which of these organisms undergoes a shift from ammonotelism to ureotelism.

3. **Analyze the Life Cycle of Frogs**:
- Frogs start their life cycle as tadpoles, which are aquatic and primarily excrete ammonia (ammonotelism). This is because they live in water, which allows for the dilution of ammonia.
- As frogs undergo metamorphosis and transition into adult frogs, they become more terrestrial. In this stage, they shift to excreting urea (ureotelism) as their primary nitrogenous waste.

4. **Compare with Other Organisms**:
- Fishes generally remain ammonotelic throughout their life as they are fully aquatic.
- Birds and mammals (including humans) are ureotelic from the beginning of their life cycle and do not shift from ammonotelism.

5. **Conclusion**:
- The organism that exhibits a shift from ammonotelism to ureotelism is the frog.

### Final Answer:
The shifting of ammonotelism to ureotelism is seen in **frogs**.

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