A : Ammonia is oxidised first to nitrate then to nitrite by the action of Nitrosomonas and Nitrobacter respectively.
R : Nitrite thus formed is absorbed by leaves.

Options

A. If both Assertion & Reason are true and the reason is the correct explanation of the assertion.
B. If both Assertion & Reason are true but the reason is not the correct explanation of the assertion.
C. If Assertion is true statement but Reason is false.
D. If both Assertion and Reason are false statements.

Answer

To solve the question regarding the assertion and reason provided, we will break down the information step by step.

### Step-by-Step Solution:

1. **Understanding the Assertion**:
- The assertion states that "Ammonia is oxidized first to nitrate then to nitrite by the action of Nitrosomonas and Nitrobacter respectively."
- This statement is incorrect. In the nitrogen cycle, ammonia (NH3) is first oxidized to nitrite (NO2-) by the bacterium Nitrosomonas, and then nitrite is further oxidized to nitrate (NO3-) by the bacterium Nitrobacter.

2. **Understanding the Reason**:
- The reason states that "Nitrite thus formed is absorbed by leaves."
- This statement is also incorrect. In plants, nitrite is not typically absorbed by the leaves; instead, it is the roots that absorb nitrate (NO3-) from the soil. Leaves primarily engage in photosynthesis and gas exchange.

3. **Evaluating the Truth of Each Statement**:
- Since the assertion is false (the order of oxidation is incorrect) and the reason is also false (the absorption of nitrite occurs at the roots, not the leaves), we conclude that both statements are incorrect.

4. **Conclusion**:
- Therefore, the correct answer to the question is that both the assertion and the reason are false.

### Final Answer:
- Both assertion and reason are false.

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