Auxin was first isolated from -

Options

A. Coleoptile of oat
B. Human urine
C. Maize
D. tea

Answer

**Step-by-Step Solution:**

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

2. **Identifying the Source of Isolation**: The question asks about the first isolation of auxin. Historically, auxin was first identified and isolated from a specific source.

3. **Evaluating the Options**: The options provided are:
- Cauliptyle of Oat
- Human Urine
- Maze
- Tea

4. **Historical Context**: The first auxin was indeed isolated from human urine. This was a significant discovery in plant physiology, as it led to the understanding of plant hormones.

5. **Conclusion**: Therefore, the correct answer to the question "Auxin was first isolated from" is **Human Urine**.

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