Which of the following is not an example of phytohormones ?

Options

A. Cytokinins
B. Ethylene
C. Auxins
D. Insulin

Answer

To determine which of the following is not an example of phytohormones, we need to first understand what phytohormones are and identify some common examples.

### Step-by-Step Solution:

1. **Definition of Phytohormones**:
- Phytohormones, also known as plant hormones, are naturally occurring organic compounds that regulate various physiological processes in plants. They play crucial roles in growth, development, and responses to environmental stimuli.

2. **Common Examples of Phytohormones**:
- Some well-known examples of phytohormones include:
- **Cytokinins**: These hormones promote cell division and growth.
- **Ethylene**: This hormone is involved in the ripening of fruits and the regulation of other growth processes.
- **Auxins**: These hormones are responsible for elongation of cells and are involved in various growth processes.

3. **Identifying the Options**:
- The question provides a list of options, among which we need to identify the one that is not a phytohormone.
- From the examples mentioned, we can confirm that cytokinins, ethylene, and auxins are indeed phytohormones.

4. **Analyzing the Given Options**:
- If one of the options is **Insulin**, we need to understand that insulin is a peptide hormone produced by the pancreas in animals, not a plant hormone.

5. **Conclusion**:
- Therefore, the correct answer to the question "Which of the following is not an example of phytohormones?" is **Insulin**.

### Final Answer:
Insulin is not an example of phytohormones.

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