Which of the following is first formed nitrogenous waste of vertebrate?

Options

A. `NH_(3)`
B. Carbon dioxide
C. Alanine
D. Urea

Answer

To determine the first formed nitrogenous waste of vertebrates, we can follow these steps:

### Step-by-Step Solution:

1. **Understanding Nitrogenous Wastes**:
- Nitrogenous wastes are the by-products of protein metabolism in animals. They must be eliminated from the body to maintain homeostasis.

2. **Identifying the Options**:
- The options provided are NH3 (ammonia), carbon dioxide, alanine, and urea. We need to analyze these substances to identify which is the first formed nitrogenous waste.

3. **Role of Proteins**:
- When proteins are metabolized, they undergo deamination, which is the removal of an amino group. This process produces ammonia (NH3) as a direct by-product.

4. **Toxicity of Ammonia**:
- Ammonia is highly toxic to the body. Therefore, it must be converted into less toxic forms for safe excretion.

5. **Conversion of Ammonia**:
- In vertebrates, ammonia is converted into urea or uric acid for excretion. However, ammonia is the first nitrogenous waste produced during protein metabolism.

6. **Conclusion**:
- Based on the analysis, the first formed nitrogenous waste in vertebrates is ammonia (NH3).

### Final Answer:
The first formed nitrogenous waste of vertebrates is **NH3 (ammonia)**.

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