A: Temperature is an important factors for growth.
R: High temperature increases the diameter of Tap root.

Options

A. If both As and R are correct and R is correct explanation of As
B. If both As and R are correct but R is not correct explanation of As
C. If As is correct, R is wrong
D. If both As and R are wrong.

Answer

### Step-by-Step Solution:

1. **Understanding the Assertion (A)**:
- The assertion states that "Temperature is an important factor for growth."
- This is true because temperature affects various physiological processes in plants, including enzyme activity, photosynthesis, and respiration.

2. **Understanding the Reason (R)**:
- The reason states that "High temperature increases the diameter of the tap root."
- This statement is false because while temperature does influence growth, excessively high temperatures can actually hinder growth and reduce the activity of enzymes, which are crucial for plant development.

3. **Evaluating the Relationship**:
- The assertion is true, but the reason provided is false.
- Therefore, the correct conclusion is that while temperature is indeed an important factor for growth, the specific claim about high temperature increasing the diameter of the tap root is incorrect.

4. **Conclusion**:
- Based on the evaluation, we can conclude that the assertion is correct while the reason is incorrect.
- Thus, the correct answer is that the assertion is true and the reason is false.

### Final Answer:
- The assertion is correct, and the reason is incorrect. Therefore, the correct option is option 3.

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