The naturally occurring growth inhibitor is

Options

A. IAA (indoleacetic acid)
B. ABA (abscisic acid)
C. NAA (naphthalene acetic acid)
D. GA (gibberellic acid)

Answer

**Step-by-Step Solution:**

1. **Understanding the Question**: The question asks for a naturally occurring growth inhibitor. This means we need to identify a substance that inhibits growth and is found naturally in plants.

2. **Identifying Plant Hormones**: Plant hormones can be categorized into two main types: growth promoters and growth inhibitors. Growth promoters encourage growth, while growth inhibitors prevent or slow down growth.

3. **Listing Growth Promoting Hormones**: Some well-known growth-promoting hormones include:
- Indole Acetic Acid (IAA)
- Indole Butyric Acid (IBA)
- Naphthalene Acetic Acid (NAA)
- Cytokinins

4. **Identifying Growth Inhibitor Hormones**: The main growth inhibitor hormone in plants is Abscisic Acid (ABA). This hormone is known to inhibit growth and is often referred to as the stress hormone because it helps plants respond to stress conditions.

5. **Evaluating the Options**:
- Option 1: Indole Acetic Acid - This is a growth promoter.
- Option 2: Abscisic Acid (ABA) - This is a growth inhibitor.
- Option 3: Naphthalene Acetic Acid - This is also a growth promoter.

6. **Conclusion**: Based on the analysis, the correct answer to the question is **Abscisic Acid (ABA)**, as it is the naturally occurring growth inhibitor in plants.

**Final Answer**: The naturally occurring growth inhibitor is Abscisic Acid (ABA).

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