The non - symbiotic anaerobic nitrogen fixer is

Options

A. Rhizobium
B. Beijerinckia
C. Azotobacter
D. None of these

Answer

To solve the question "The non-symbiotic anaerobic nitrogen fixer is," we will analyze the options provided and determine which one fits the criteria of being a non-symbiotic anaerobic nitrogen-fixing bacterium.

### Step-by-Step Solution:

1. **Understanding Nitrogen Fixation**:
- Nitrogen fixation is the process by which atmospheric nitrogen (N₂) is converted into ammonia (NH₃), which plants can utilize. This process is crucial for the nitrogen cycle.

2. **Identifying Types of Nitrogen Fixers**:
- There are two main types of nitrogen-fixing bacteria:
- **Symbiotic Nitrogen Fixers**: These bacteria form a symbiotic relationship with plants (e.g., legumes).
- **Non-Symbiotic (Free-living) Nitrogen Fixers**: These bacteria do not form a symbiotic relationship and can live independently in the soil.

3. **Analyzing the Options**:
- **Rhizobium**: This is a symbiotic nitrogen-fixing bacterium that forms a relationship with leguminous plants. Therefore, it does not fit the criteria of being non-symbiotic.
- **Basarnica**: This option is not commonly recognized in the context of nitrogen fixation, and it may be a typographical error or a less-known term.
- **Azotobacter**: This is a free-living nitrogen-fixing bacterium, but it is aerobic, meaning it requires oxygen for its metabolic processes. Hence, it does not fit the anaerobic requirement.
- **None of these**: This option suggests that none of the provided options are correct.

4. **Conclusion**:
- Since we are looking for a non-symbiotic anaerobic nitrogen fixer, and given the options, the correct answer is **Basarnica**, assuming it is meant to refer to a non-symbiotic anaerobic nitrogen-fixing bacterium. However, if this is not a recognized term, the answer would be **none of these**.

### Final Answer:
The correct answer is **none of these** (assuming Basarnica is not a recognized non-symbiotic anaerobic nitrogen fixer).