An advantage of excreting nitrogenous wastes in the form of uric acid is that

Options

A. Uric acid can be excreted in almost solid form
B. Uric acid is the first metabolic breakdown products of acids
C. Uric acid is the second metabolic breakdown products of acids
D. Uric acid may be excreted through the lungs

Answer

### Step-by-Step Solution:

1. **Understanding Nitrogenous Wastes**:
- All organisms produce nitrogenous wastes as a result of protein metabolism. The primary forms of nitrogenous waste include ammonia, urea, and uric acid.

2. **Toxicity of Nitrogenous Wastes**:
- Ammonia is highly toxic and requires a large amount of water to be safely excreted. This is why aquatic organisms, which have access to abundant water, can afford to excrete ammonia directly.

3. **Adaptations in Terrestrial Animals**:
- Terrestrial animals, on the other hand, face a challenge due to limited water availability. Therefore, they have evolved to excrete nitrogenous waste in less toxic forms such as urea or uric acid.

4. **Uric Acid Excretion**:
- Uric acid is less toxic than ammonia and can be excreted in a semi-solid form (as pellets or paste). This adaptation is particularly seen in reptiles, birds, and land snails.

5. **Water Conservation**:
- The primary advantage of excreting nitrogenous waste as uric acid is that it allows these organisms to conserve water. Since uric acid can be excreted with minimal water loss, it is an efficient way to manage nitrogenous waste in environments where water is scarce.

6. **Conclusion**:
- Therefore, the advantage of excreting nitrogenous wastes in the form of uric acid is that it enables organisms to conserve water while effectively eliminating less toxic waste.

### Final Answer:
The advantage of excreting nitrogenous wastes in the form of uric acid is that it allows for minimal water loss, as uric acid can be excreted in a semi-solid form.

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