Assertion :`C_(4)` photosynthesis is more sensitive to low temperature as compared to `C_(3)` photosynthesis .
Reason : the rubisco found in `C_(4)` plants is more sensitive to low temperature as compared to `C_(3)` plants.

Options

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

Answer

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

### Step-by-Step Solution:

1. **Understanding the Assertion**:
- The assertion states that "C4 photosynthesis is more sensitive to low temperature as compared to C3 photosynthesis."
- C4 plants are adapted to high light intensity and high temperatures. However, they can experience a decrease in photosynthetic efficiency at low temperatures.

2. **Understanding the Reason**:
- The reason states that "the Rubisco found in C4 plants is more sensitive to low temperature as compared to C3 plants."
- Rubisco is the enzyme responsible for fixing carbon dioxide in the Calvin cycle, which is a part of C3 photosynthesis. In C4 plants, the primary enzyme for carbon fixation is PEP carboxylase, not Rubisco.

3. **Evaluating the Assertion**:
- The assertion is true because C4 photosynthesis does indeed show a decline in efficiency at low temperatures compared to C3 photosynthesis.

4. **Evaluating the Reason**:
- The reason is false. While C4 plants are sensitive to low temperatures, it is not due to Rubisco being more sensitive. Instead, it is the PEP carboxylase enzyme that is more relevant in C4 photosynthesis and is affected by temperature.

5. **Conclusion**:
- Since the assertion is true and the reason is false, the correct answer is that the assertion is true but the reason is false.

### Final Answer:
The correct option is: **Assertion is true but reason is false.**

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