Pick the odd one out

Options

A. Pseudomonas
B. Nitrosomonas
C. Nitrobacter
D. Nitrosococcus

Answer

**Step-by-Step Solution:**

1. **Identify the Options**: The options provided are Pseudomonas, Nitrosomonas, and potentially other bacteria that are not explicitly mentioned but are implied to be similar to Nitrosomonas.

2. **Classify the Bacteria**:
- **Pseudomonas**: This is identified as a denitrifying bacterium. Denitrifying bacteria convert nitrates into nitrogen gas, which is released into the atmosphere.
- **Nitrosomonas**: This is classified as a nitrifying bacterium. Nitrifying bacteria convert ammonia into nitrites and then into nitrates, which are usable forms of nitrogen for plants.

3. **Compare the Functions**:
- **Denitrifying Bacteria (Pseudomonas)**: Their role is to reduce nitrates to nitrogen gas, thus removing nitrogen from the soil.
- **Nitrifying Bacteria (Nitrosomonas)**: Their role is to convert ammonia into nitrites and then into nitrates, thus adding nitrogen to the soil.

4. **Identify the Odd One Out**: Since Pseudomonas is a denitrifying bacterium and Nitrosomonas is a nitrifying bacterium, the odd one out is Pseudomonas because it performs a different function compared to Nitrosomonas and other nitrifying bacteria.

5. **Conclusion**: The correct answer to the question "Pick the odd one out" is **Pseudomonas**.

**Final Answer**: Pseudomonas (Option A) is the odd one out.

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