Assertion :- Diffusion is one of the most important process of plants.
Reason:- Diffusion is the only means for gaseous movement within plant body.

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

Answer

### Step-by-Step Solution:

1. **Understanding the Assertion**: The assertion states that "Diffusion is one of the most important processes of plants."
- **Explanation**: Diffusion is indeed a crucial process in plants as it facilitates the movement of substances such as gases (oxygen and carbon dioxide) and nutrients across cell membranes without the need for energy.

2. **Understanding the Reason**: The reason states that "Diffusion is the only means for gaseous movement within the plant body."
- **Explanation**: This statement is also true. In plants, gases move primarily through diffusion, which allows for the exchange of gases necessary for processes like photosynthesis and respiration.

3. **Evaluating the Relationship**: We need to determine if the reason correctly explains the assertion.
- **Explanation**: Since diffusion is essential for gas exchange in plants, the reason supports the assertion by explaining why diffusion is important.

4. **Conclusion**: Both the assertion and the reason are correct, and the reason accurately explains the assertion.
- Therefore, the correct option is that both the assertion and reason are correct and the reason explains the assertion.

### Final Answer:
Both the assertion and reason are correct, and the reason explains the assertion.

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