The process of conversion of `NO_(2), NO_(3), NH_(3) " to "N_(2)` is called ________ and is done by

Options

A. Nitrification, Nitrosomonas
B. Denitrification, Pseudomonas
C. Nitrate assimilation, Nitrogenase
D. Ammonification, Bacillus

Answer

### Step-by-Step Solution:

1. **Understanding the Question**: The question asks about the process that converts nitrates (NO₃) and ammonia (NH₃) into nitrogen gas (N₂). This process is a part of the nitrogen cycle.

2. **Identifying the Process**: The conversion of nitrates and ammonia into nitrogen gas is known as **denitrification**. This process is essential for returning nitrogen to the atmosphere.

3. **Identifying the Organisms Involved**: Denitrification is primarily carried out by specific types of bacteria. The key organisms involved in this process include:
- **Thiobacillus**
- **Pseudomonas**

4. **Final Answer**: Therefore, the complete answer to the question is:
- The process of conversion of NO₂, NO₃, and NH₃ to N₂ is called **denitrification** and is done by **Thiobacillus** and **Pseudomonas**.