Chemically , auxin is

Options

A. Indole acetic acid
B. Kinetin
C. Diterpenes
D. Amino purine

Answer

To solve the question "Chemically, auxin is:", we need to analyze the options provided and identify which one correctly represents the chemical nature of auxin.

### Step-by-Step Solution:

1. **Understanding Auxin**: Auxins are a class of plant hormones that play a crucial role in plant growth and development. The most common and well-studied auxin is indole-3-acetic acid (IAA).

2. **Analyzing the Options**:
- **Option A: Indole Acetic Acid**: This is indeed the primary and most recognized form of auxin in plants. It is derived from the amino acid tryptophan and is crucial for various growth processes.
- **Option B: Kinatin**: This is related to cytokinins, another class of plant hormones that promote cell division.
- **Option C: Diterpenes**: These are a class of terpenes that can serve as precursors for gibberellic acid, which is another type of plant hormone but not auxin.
- **Option D: Aminopurine**: This is also related to cytokinins and does not represent auxin.

3. **Conclusion**: Given the analysis, the correct answer is **Option A: Indole Acetic Acid**, as it is the chemical that defines auxin.

### Final Answer:
Chemically, auxin is **Indole Acetic Acid**.

---