Assertion : Dark reactions of photosynthesis are temperauture -controlled processes.
Reason : Most of the reactions are enzymatic in nature.

Options

A. If both Assertion and Reason are true and the Reason is the correct explanation
B. If both Assertion and Reason are true, but the Reason is not the correct explanation of the Assertion.
C. If Assertion is true, but Reason is false.
D. If both Assertion and Reason are false.

Answer

To solve the question, we need to analyze the assertion and the reason provided.

### Step-by-Step Solution:

1. **Understanding the Assertion**:
- The assertion states that "Dark reactions of photosynthesis are temperature-controlled processes."
- Dark reactions, also known as the Calvin cycle, occur in the stroma of chloroplasts and are influenced by temperature. As temperature affects enzyme activity, it also impacts the rate of these reactions.

2. **Understanding the Reason**:
- The reason states that "Most of the reactions are enzymatic in nature."
- This is true because dark reactions involve various enzymes, such as RuBisCO, which catalyze the reactions necessary for carbon fixation and the synthesis of glucose.

3. **Evaluating the Truth of Both Statements**:
- Both the assertion and the reason are true. Dark reactions are indeed temperature-controlled due to the influence of temperature on enzyme activity, and most reactions in the dark phase are enzymatic.

4. **Determining the Relationship Between Assertion and Reason**:
- While both statements are true, the reason does not directly explain the assertion. The assertion is about temperature control, while the reason discusses enzymatic nature. The temperature control is a broader concept that includes but is not limited to enzymatic reactions.

5. **Conclusion**:
- Since both the assertion and the reason are true, but the reason does not provide a correct explanation for the assertion, the correct answer is that both statements are true, but the reason is not the correct explanation of the assertion.

### Final Answer:
Both assertion and reason are true, but the reason is not the correct explanation of the assertion.