Which one of the following pairs, is not correctly matched?

Options

A. Abscisic acid - Stomatal closure
B. Gibberellic acid - Leaf fall
C. Cytokinin - Cell division
D. IAA -Cell wall elongation

Answer

To determine which pair is not correctly matched, we need to analyze each option provided in the question. Here’s a step-by-step breakdown:

### Step 1: Analyze the first option
- **Pair**: Abscisic acid - Stomatal closure
- **Explanation**: Abscisic acid (ABA) is known to promote stomatal closure during stress conditions (like drought). This pair is correctly matched.

### Step 2: Analyze the second option
- **Pair**: Gibberellic acid - Leaf fall
- **Explanation**: Gibberellic acid (GA) is primarily involved in promoting growth, such as stem elongation and seed germination. It does not cause leaf fall; that is the role of ethylene. Therefore, this pair is incorrectly matched.

### Step 3: Analyze the third option
- **Pair**: Cytokinins - Cell division
- **Explanation**: Cytokinins are known to promote cell division and are involved in various growth processes. This pair is correctly matched.

### Step 4: Analyze the fourth option
- **Pair**: IAA (Indole-3-acetic acid) - Cell elongation
- **Explanation**: IAA is a type of auxin that promotes cell elongation. This pair is also correctly matched.

### Conclusion
The only incorrectly matched pair is the second option: Gibberellic acid - Leaf fall. The correct answer is therefore the second option.

### Final Answer
The pair that is not correctly matched is:
**Gibberellic acid - Leaf fall**

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