The rosette habit of cabbage can be changed by applicaton of

Options

A. ABA
B. IAA
C. GA
D. Ethephon.

Answer

### Step-by-Step Solution:

1. **Understanding the Rosette Habit**:
- The rosette habit in plants, such as cabbage, refers to a growth form where leaves are arranged in a circular pattern close to the ground, resulting in a short stem and compact structure.

2. **Identifying the Role of Plant Hormones**:
- Plant hormones, or phytohormones, play a crucial role in regulating growth and development in plants. Different hormones have specific functions that can influence various growth patterns.

3. **Gibberellic Acid (GA)**:
- Gibberellic acid is a plant hormone that promotes stem elongation and can change the rosette habit of plants. It is known to induce a process called "bolting," where the plant rapidly elongates its stem.

4. **Conditions for Bolting**:
- Bolting typically requires long daylight hours or a cold treatment. However, it can also be induced artificially by applying gibberellic acid, even under normal conditions.

5. **Evaluating Other Hormones**:
- **Abscisic Acid (ABA)**: This hormone is involved in processes like seed dormancy and stomatal closure, and does not promote stem elongation.
- **Indole-3 Acetic Acid (IAA)**: While this auxin affects plant growth, it primarily influences cell elongation and differentiation rather than promoting bolting.
- **Ethylene (Ethiphone)**: This hormone is mainly involved in fruit ripening and flower induction, and does not affect the rosette habit.

6. **Conclusion**:
- Based on the functions of these hormones, the application of gibberellic acid (GA) is the correct method to change the rosette habit of cabbage to a more elongated form.

### Final Answer:
The rosette habit of cabbage can be changed by the application of gibberellic acid (GA).

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