Pseudomonas is an important component nitrogen cycle. It

Options

A. Fixes elemental nitrogen
B. Produces elemental nitrogen
C. Transfer nirogen
D. Changes ammonium nitrogen to nitrate state

Explanation

### Step-by-Step Solution:

1. **Understanding Pseudomonas**:
- Pseudomonas is a type of bacteria that plays a crucial role in the nitrogen cycle. It is specifically known for its role in the process of denitrification.

**Hint**: Think about the role of bacteria in nutrient cycles, particularly in converting nitrogen forms.

2. **Denitrification Process**:
- Denitrification is the process by which nitrates (NO3-) and nitrites (NO2-) are converted into nitrogen gas (N2) by bacteria such as Pseudomonas. This process helps to remove excess nitrogen from the soil and return it to the atmosphere.

**Hint**: Recall the steps of the nitrogen cycle and where denitrification fits in.

3. **Conversion of Ionic Nitrogen**:
- Pseudomonas converts ionic forms of nitrogen (like nitrates and nitrites) into nitrogen gas. This is essential for maintaining the balance of nitrogen in the ecosystem.

**Hint**: Focus on what happens to nitrogen compounds in the soil and how they are transformed.

4. **Comparison with Other Bacteria**:
- While Pseudomonas is a denitrifying bacterium, there are other bacteria, such as Thiobacillus, that also perform similar functions in the nitrogen cycle.

**Hint**: Consider the diversity of bacteria involved in nitrogen transformations.

5. **Identifying the Correct Statement**:
- From the options provided, the correct statement regarding Pseudomonas is that it produces elemental nitrogen (N2) as a result of the denitrification process.

**Hint**: Evaluate each option carefully, considering what each type of bacteria does in the nitrogen cycle.

### Summary:
Pseudomonas is a denitrifying bacterium that converts ionic forms of nitrogen into nitrogen gas, playing a vital role in the nitrogen cycle by returning nitrogen to the atmosphere.