The most common auxin is

Options

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

Answer

**Step-by-Step Solution:**

1. **Understanding Auxins**: Auxins are a class of plant hormones that play a crucial role in growth and development. They are involved in various processes such as cell elongation, root formation, and fruit development.

2. **Identifying Common Auxins**: Among the various types of auxins, several are known, including:
- GA (Gibberellins)
- ABA (Abscisic Acid)
- Kinetin
- IAA (Indole-3-acetic acid)

3. **Recognizing IAA**: Indole-3-acetic acid (IAA) is recognized as the most common and naturally occurring auxin in plants. It is the primary auxin that is synthesized in plants and is responsible for many of the growth responses.

4. **Conclusion**: Based on the information, the most common auxin is IAA (Indole-3-acetic acid).

5. **Final Answer**: The correct option is option 4, IAA.

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