cosider the following conversions of nitrogen cycle. Which one of the following repersents biological oxidation Process?

Options

A. `NH_(3) to NO_(3)`
B. `NO_(3)^(-) to N_(2)`
C. `NO_(3)^(-) to NH_(3)`
D. `N_(2) to NH_(3)`

Answer

To determine which process in the nitrogen cycle represents a biological oxidation process, we can analyze the given options step by step.

### Step-by-Step Solution:

1. **Understanding Biological Oxidation**:
- Biological oxidation refers to the process where a substance loses electrons, typically involving the conversion of a reduced form of a compound to a more oxidized form. In the nitrogen cycle, this often involves the conversion of ammonia (NH₃) to nitrite (NO₂⁻) and then to nitrate (NO₃⁻).

2. **Analyzing the Given Processes**:
- **Process 1**: Ammonia (NH₃) is converted into Nitrate (NO₃⁻).
- This process involves the oxidation of ammonia to nitrite and then to nitrate. Therefore, this represents a biological oxidation process.

- **Process 2**: Nitrate (NO₃⁻) is converted into Atmospheric Nitrogen (N₂).
- This process involves the reduction of nitrate to nitrogen gas, which is not an oxidation process.

- **Process 3**: Nitrate (NO₃⁻) is converted into Ammonia (NH₃).
- This process also involves reduction, as nitrate is being converted back to ammonia.

- **Process 4**: Atmospheric Nitrogen (N₂) is converted into Ammonia (NH₃).
- This process is known as nitrogen fixation and is also not an oxidation process; it involves the reduction of nitrogen gas to ammonia.

3. **Conclusion**:
- The only process that represents biological oxidation is the first one: **Ammonia (NH₃) is converted into Nitrate (NO₃⁻)**.

### Final Answer:
The process that represents a biological oxidation process is: **Ammonia is converted into Nitrate**.