Which bacteria have the ability to convert atmospheric nitrogen to nitrates?

Options

A. Nitrobacter
B. Nitrosomonas
C. Rhizobium
D. Clostridium

Explanation

To answer the question "Which bacteria have the ability to convert atmospheric nitrogen to nitrates?", we can follow these steps:

### Step-by-Step Solution:

1. **Understanding Nitrogen Fixation**:
- Plants require nitrogen for their growth but cannot directly utilize atmospheric nitrogen (N₂). They need it in a form that is usable, such as nitrates (NO₃⁻).

2. **Role of Bacteria**:
- Certain bacteria have the ability to convert atmospheric nitrogen into nitrates through a process known as nitrogen fixation. This process is crucial for making nitrogen available to plants.

3. **Identifying Nitrifying Bacteria**:
- The bacteria responsible for this conversion are known as nitrifying bacteria. They play a vital role in the nitrogen cycle, transforming nitrogen from the atmosphere into forms that plants can absorb.

4. **Specific Bacteria**:
- Among the nitrifying bacteria, one of the key groups is from the family Nitrobacteraceae. The bacteria in this family, such as Nitrobacter, are specifically known for converting nitrites (NO₂⁻) into nitrates (NO₃⁻).

5. **Conclusion**:
- The correct answer to the question is **Nitrobacter**, which is a type of nitrifying bacteria that helps in the conversion of atmospheric nitrogen into nitrates.

### Final Answer:
The bacteria that have the ability to convert atmospheric nitrogen to nitrates are **Nitrobacter**.

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