Assertion: Ammonia is converted into nitrate by soil bacteria like Nitrosomonas and Nitrobacter
Reason: Denitrification is carried by bacteria Pseudomonas and Azotobacter.

Options

A. If both assertion and reason are true and reason is the correct explanation of assertion
B. if both assertion and reason are true but reason is not the correct explanation of assertion
C. if assertion is true but reason is false
D. if both assertion and reason are false

Explanation

### Step-by-Step Solution:

1. **Understanding the Assertion**: The assertion states that "Ammonia is converted into nitrate by soil bacteria like Nitrosomonas and Nitrobacter." This is a true statement. In the nitrogen cycle, ammonia (NH3) is indeed converted into nitrate (NO3-) through a process called nitrification, which involves two steps:
- Ammonia is first converted to nitrite (NO2-) by bacteria such as Nitrosomonas.
- Then, nitrite is further converted to nitrate by bacteria such as Nitrobacter.

2. **Understanding the Reason**: The reason states that "Denitrification is carried out by bacteria Pseudomonas and Azotobacter." This statement is partially true. While it is correct that denitrification is a process where nitrates are converted back to nitrogen gas (N2) and released into the atmosphere, only Pseudomonas is a known denitrifying bacterium. Azotobacter, on the other hand, is primarily involved in nitrogen fixation and does not play a significant role in denitrification.

3. **Evaluating the Relationship**: The assertion is true because it accurately describes the process of nitrification. The reason is false because it incorrectly includes Azotobacter as a denitrifying bacterium. Therefore, the reason does not correctly explain the assertion.

4. **Conclusion**: Based on the evaluation, the correct answer is that the assertion is true, but the reason is false.

### Final Answer:
Assertion is true, but reason is false.

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