Assertion : When `CO_(2)` concentration of atmosphere increases, stomata close partially.
Reason : `CO_(2)` combines with water to form carbonic acid which lowers pH value ans stomata close.

Options

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

Answer

To analyze the assertion and reason provided in the question, we can break it down into a step-by-step solution:

### Step 1: Understand the Assertion
- **Assertion**: When \( CO_2 \) concentration of the atmosphere increases, stomata close partially.
- **Explanation**: Stomata are small openings on the surface of leaves that regulate gas exchange. When \( CO_2 \) levels rise, plants may partially close their stomata to reduce water loss and maintain homeostasis.

### Step 2: Understand the Reason
- **Reason**: \( CO_2 \) combines with water to form carbonic acid, which lowers pH value, and stomata close.
- **Explanation**: When \( CO_2 \) enters the leaf, it reacts with water to form carbonic acid (H2CO3). This reaction can lead to a decrease in pH, which may influence the closing of stomata.

### Step 3: Evaluate the Relationship Between Assertion and Reason
- Both the assertion and the reason are true statements. However, the reason provided does not directly explain why the stomata close in response to increased \( CO_2 \) concentration. The closure of stomata is primarily a response to conserve water and regulate gas exchange rather than being solely due to the formation of carbonic acid.

### Step 4: Determine the Correct Option
- Given that both the assertion and the reason are true, but the reason does not correctly explain the assertion, the correct option would be:
- **Both assertion and reason are true, but reason is not a correct explanation of assertion.**

### Final Answer:
The correct option is: **Both assertion and reason are true, but reason is not a correct explanation of assertion.**

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