Conversion of ammonia into nitrite and nitrate is

Options

A. Ammonification
B. Denitrification
C. Nitrification
D. All the above.

Answer

### Step-by-Step Solution:

1. **Understanding the Question**: The question asks about the conversion of ammonia into nitrite and nitrate. This process is a part of the nitrogen cycle.

2. **Identifying the Process**: The specific process that converts ammonia (NH₃) into nitrite (NO₂⁻) and then into nitrate (NO₃⁻) is known as nitrification.

3. **Bacterial Involvement**: Nitrification is carried out by specific types of bacteria known as nitrifying bacteria. The two main groups involved in this process are:
- **Nitrosomonas**: These bacteria convert ammonia into nitrite.
- **Nitrobacter**: These bacteria convert nitrite into nitrate.

4. **Evaluating the Options**:
- **Option 1: Ammonification**: This process involves the conversion of organic nitrogen into ammonia, not the conversion of ammonia into nitrite and nitrate. Therefore, this option is incorrect.
- **Option 2: Denitrification**: This process involves the conversion of nitrates and nitrites back into nitrogen gas, which is the opposite of what the question is asking. Thus, this option is also incorrect.
- **Option 3: Nitrification**: As discussed, this is the correct process where ammonia is converted into nitrite and then nitrate.
- **Option 4: All of the above**: Since only nitrification is the correct answer, this option is incorrect.

5. **Conclusion**: The correct answer to the question is **Option 3: Nitrification**.