Excretory product of birds and reptiles is

Options

A. Urea
B. Uric acid
C. Ammonia
D. TMO

Answer

### Step-by-Step Solution:

1. **Identify the Excretory Products**: The question asks for the excretory product of birds and reptiles. The options provided are urea, uric acid, ammonia, and TMO.

2. **Understand the Habitat of Birds and Reptiles**: Birds and reptiles are primarily terrestrial organisms, which means they live on land where water availability is limited.

3. **Consider the Toxicity of Ammonia**: Ammonia is a common nitrogenous waste product produced from protein metabolism. However, it is highly toxic and requires a large amount of water for its excretion.

4. **Adaptation to Limited Water Availability**: Due to the limited availability of water in their environment, birds and reptiles cannot afford to excrete ammonia directly. Instead, they convert ammonia into a less toxic substance.

5. **Identify the Less Toxic Waste**: The less toxic waste product that birds and reptiles excrete is uric acid. Uric acid is less soluble in water and requires significantly less water for its elimination compared to ammonia.

6. **Define the Mode of Excretion**: The process of excreting uric acid is known as uricotelism. Birds and reptiles are classified as uricotelic organisms because they excrete uric acid as their primary nitrogenous waste.

7. **Evaluate the Other Options**:
- Urea is the primary waste product in humans (ureotelic organisms) and requires more water for excretion.
- Ammonia is primarily excreted by aquatic organisms like fish, where water is abundant.
- TMO is not a recognized nitrogenous waste product in the context of this question.

8. **Conclusion**: Based on the above reasoning, the correct answer to the question is **uric acid**.

### Final Answer: Uric Acid

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