Assertion. The atmospheric concentration of `CO_(2)` at which photosynthesis just compensates for respiration is referred to as `CO_(2)` compensation point.

Reason. `CO_(2)`-compensation point is reached when the amount of `CO_(2)` uptake is less than that generated through respiration because the level of `CO_(2)` is more than that required for achieving `CO_(2)`-compensation point.

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 question regarding the assertion and reason related to the CO₂ compensation point, we can break it down into the following steps:

### Step 1: Understand the Assertion
The assertion states that the atmospheric concentration of CO₂ at which photosynthesis just compensates for respiration is referred to as the CO₂ compensation point.

**Explanation:**
- At the CO₂ compensation point, the rate of photosynthesis equals the rate of respiration. This means that the amount of CO₂ taken up by the plant during photosynthesis is equal to the amount of CO₂ released during respiration.

### Step 2: Analyze the Reason
The reason provided states that the CO₂ compensation point is reached when the amount of CO₂ uptake is less than that generated through respiration because the level of CO₂ is more than that required for achieving the CO₂ compensation point.

**Explanation:**
- This statement is incorrect. At the CO₂ compensation point, the uptake of CO₂ should equal the amount generated through respiration, not less. Therefore, the reason does not accurately explain the assertion.

### Step 3: Determine the Truth of Assertion and Reason
- The assertion is **true** because it correctly defines the CO₂ compensation point.
- The reason is **false** because it incorrectly describes the relationship between CO₂ uptake and respiration at the compensation point.

### Step 4: Conclusion
Based on the analysis:
- The correct conclusion is that the assertion is true, and the reason is false.

Thus, the answer to the question is that the assertion is true, and the reason is false.

### Final Answer:
The correct option is: **A is true, R is false.**

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