Which one prevents premature fall of fruit ?

Options

A. NAA
B. Ethylene
C. `GA_(3)`
D. Zeatin.

Answer

**Step-by-Step Solution:**

1. **Understanding the Question**: The question asks which substance prevents the premature fall of fruit. This indicates we need to identify a plant hormone or substance that plays a role in fruit retention.

2. **Identifying Relevant Plant Hormones**: The options provided are NAA, Ethylene, GA3, and Zeatin. We need to analyze each option to determine which one is responsible for preventing fruit drop.

3. **Analyzing NAA (Naphthalene Acetic Acid)**: NAA is a synthetic auxin. Auxins are known to prevent the abscission (falling off) of leaves and fruits. Young leaves and fruits produce auxins, which help them remain attached to the plant.

4. **Understanding Ethylene**: Ethylene is a plant hormone associated with fruit ripening. It actually promotes the abscission process, leading to the fall of fruits. Therefore, it does not prevent premature fruit drop.

5. **Evaluating GA3 (Gibberellic Acid)**: GA3 is a type of gibberellic acid that promotes growth and elongation in plants but does not specifically prevent fruit drop. Thus, it is not the correct answer.

6. **Considering Zeatin**: Zeatin is a type of cytokinin, which primarily promotes cell division and growth but does not have a role in preventing fruit drop. Hence, it is also not the correct answer.

7. **Conclusion**: After analyzing all the options, NAA (Naphthalene Acetic Acid) is identified as the substance that prevents the premature fall of fruit. Therefore, the correct answer is NAA.

**Final Answer**: NAA (Naphthalene Acetic Acid) prevents premature fall of fruit.

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