Auxins were first isolated from

Options

A. Coleoptiles of canary grass
B. Coleoptiles of canary Avena
C. Rice seedling
D. Human urine

Answer

**Step-by-Step Solution:**

1. **Understanding Auxins**: Auxins are a class of plant hormones that play a crucial role in regulating plant growth and development.

2. **Historical Context**: The isolation of auxins dates back to 1928 when significant research was conducted on plant hormones.

3. **Key Figure**: The Dutch botanist Fritz W. Went is credited with the first successful isolation of auxins.

4. **Isolation Process**: Went isolated auxins from various sources, and the first successful isolation was from human urine.

5. **Further Discoveries**: After the initial isolation from human urine, auxins were also found in fungi and later in higher plants.

6. **Conclusion**: Based on the historical context and the sources from which auxins were isolated, the answer to the question is that auxins were first isolated from human urine.

**Final Answer**: Auxins were first isolated from human urine.

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