Naturally occurring auxin is

Options

A. NAA
B. 2, 4-D
C. MH
D. IAA

Answer

**Step-by-Step Solution:**

1. **Understanding Auxins**: Auxins are a class of plant hormones that play a crucial role in regulating plant growth. They are involved in various processes such as cell elongation, apical dominance, and phototropism.

2. **Identifying the Options**: The question provides four options: NAA, 2,4-D, MH, and IAA. We need to determine which of these is a naturally occurring auxin.

3. **Analyzing Each Option**:
- **NAA (Naphthalene Acetic Acid)**: This is a synthetic auxin, not naturally occurring in plants.
- **2,4-D (2,4-Dichlorophenoxyacetic Acid)**: This is also a synthetic auxin used in herbicides and is not found naturally in plants.
- **MH (Maleic Hydrazide)**: This is a synthetic compound that acts as a growth regulator, but it is not an auxin.
- **IAA (Indole Acetic Acid)**: This is a naturally occurring auxin that is produced in plants.

4. **Conclusion**: Based on the analysis, the only naturally occurring auxin among the options is IAA (Indole Acetic Acid).

5. **Final Answer**: The correct answer is option 4: IAA (Indole Acetic Acid).

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