Assertion: `C_(4)` photosynthetic pathway is more efficient than the `C_(3)` pathway.
Reason : Photorespiration is suppressed in `C_(4)` 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 and R is false
D. If both A and R are false

Answer

To solve the assertion and reason question regarding the efficiency of the C4 photosynthetic pathway compared to the C3 pathway, let's break it down step by step:

### Step-by-Step Solution:

1. **Understanding the Assertion**:
- The assertion states that the C4 photosynthetic pathway is more efficient than the C3 pathway.
- This is true because C4 plants have adaptations that allow them to fix carbon dioxide more effectively under certain conditions, particularly in high temperatures and low CO2 concentrations.

2. **Understanding the Reason**:
- The reason given is that photorespiration is suppressed in C4 plants.
- This is also true. In C4 plants, the enzyme PEP carboxylase is used for the initial fixation of CO2, which does not have an affinity for oxygen. This reduces the occurrence of photorespiration, a process that occurs in C3 plants when the enzyme RuBisCO reacts with oxygen instead of carbon dioxide.

3. **Connecting Assertion and Reason**:
- The reason explains why the assertion is true. Since C4 plants suppress photorespiration, they can utilize carbon dioxide more efficiently, leading to higher photosynthetic efficiency compared to C3 plants.

4. **Conclusion**:
- Both the assertion and reason are true, and the reason correctly explains the assertion. Therefore, the correct answer is that both statements are true, and the reason is the correct explanation of the assertion.

### Final Answer:
Both the assertion and reason are true, and the reason is the correct explanation of the assertion.

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