Which one of the following pairs is not correctly matched?

Options

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

Answer

To determine which pair is not correctly matched, we will analyze each option provided in the question regarding plant hormones and their functions.

### Step-by-Step Solution:

1. **Analyze the first option: Gibberellic Acid (GA) - Leaf Fall**
- Gibberellic Acid is known for promoting growth, particularly in stem elongation and seed germination. It does not cause leaf fall; instead, leaf fall is primarily associated with abscisic acid.
- **Conclusion**: This pair is incorrectly matched.

2. **Analyze the second option: Cytokinin - Cell Division**
- Cytokinins are plant hormones that promote cell division and growth. They play a crucial role in the process of cell division in plants.
- **Conclusion**: This pair is correctly matched.

3. **Analyze the third option: IAA (Indole-3-Acetic Acid) - Cell Wall Elongation**
- IAA is a type of auxin that is responsible for cell elongation and growth, particularly in stems. It promotes the elongation of cells, which leads to growth.
- **Conclusion**: This pair is correctly matched.

4. **Analyze the fourth option: Abscisic Acid - Closes Stomata**
- Abscisic Acid is known for its role in stress responses, including the closure of stomata during drought conditions to reduce water loss.
- **Conclusion**: This pair is correctly matched.

### Final Answer:
The pair that is not correctly matched is **Gibberellic Acid - Leaf Fall** (Option 1).