Which of these plant hormones allows the plant to withstand extremely dry climates ?

Options

A. ABA
B. Auxin
C. Cytokinin
D. GA

Answer

**Step-by-Step Solution:**

1. **Understanding the Question**: The question asks which plant hormone helps plants survive in extremely dry climates.

2. **Identifying the Options**: The options provided are:
- ABA (Abscisic Acid)
- Auxin
- Cytokinin
- Zyberlin

3. **Analyzing Each Hormone**:
- **ABA (Abscisic Acid)**: This hormone is known as a stress hormone. It is produced in response to stress conditions, particularly water stress. It plays a crucial role in helping plants cope with drought by promoting the closure of stomata, which are small openings on the leaves that allow for gas exchange and transpiration.
- **Auxin**: This hormone is primarily involved in growth processes such as apical dominance and fruit development (parthenocarpy). It does not play a significant role in drought resistance.
- **Cytokinin**: This hormone is mainly responsible for promoting cell division and delaying aging (senescence) in plants. It does not directly help plants withstand dry conditions.
- **Zyberlin**: This hormone is associated with internodal elongation and seed germination. It does not contribute to drought resistance.

4. **Conclusion**: Among the given options, ABA (Abscisic Acid) is the hormone that allows plants to withstand extremely dry climates by inducing stomatal closure, thereby conserving water.

5. **Final Answer**: The correct answer is **ABA (Abscisic Acid)**.

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