Metamorphosis of insects is regulated through hormone

Options

A. pheromone
B. thyroxine
C. ecdysone
D. All of these

Explanation

To answer the question regarding which hormone regulates the metamorphosis of insects, we can follow these steps:

### Step-by-Step Solution:

1. **Understand the Concept of Metamorphosis**:
- Metamorphosis is the biological process through which insects undergo significant changes in their form and structure during their life cycle, typically from larva to adult.

2. **Identify the Hormones Mentioned**:
- The question provides several options: pheromone, thyroxin, ectysin, and all of these.

3. **Analyze Each Hormone**:
- **Pheromone**: This is a chemical substance produced by animals that affects the behavior of other individuals of the same species. It does not regulate metamorphosis in insects.
- **Thyroxine**: This hormone is primarily associated with the metamorphosis of amphibians, such as frogs, and is not involved in insect metamorphosis.
- **Ectysin**: This hormone is specifically responsible for regulating the metamorphosis in insects. It plays a crucial role in the transition from larval stages to adult forms.

4. **Conclusion**:
- Based on the analysis, the hormone that regulates the metamorphosis of insects is **ectysin**.

### Final Answer:
The correct answer is **ectysin**.

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