Addition of which element in water speeds up the metamorphosis in frog's tadpole larva?

Options

A. Iodine
B. `K^(+)`
C. `Na^(+)`
D. Chloride

Answer

**Step-by-Step Solution:**

1. **Understanding Metamorphosis**: Metamorphosis in frogs refers to the transformation from the tadpole stage to the adult frog stage. This process involves significant physical changes.

2. **Identifying the Role of Hormones**: The metamorphosis in frogs is regulated by hormones, particularly thyroid hormones. These hormones are crucial for the development and transformation of the tadpole.

3. **Considering the Element Iodine**: Iodine is an essential component of thyroid hormones. When iodine is added to water, it can enhance the production of these hormones in the tadpole.

4. **Evaluating Other Elements**:
- **Potassium**: While potassium is important for muscle function and other bodily processes, it does not play a direct role in the metamorphosis of tadpoles.
- **Sodium**: Sodium is primarily involved in maintaining electrolyte balance in the body and does not influence the metamorphosis process.
- **Chloride**: Chloride also helps maintain electrolyte balance and acid-base balance in the body but is not involved in the metamorphosis of frogs.

5. **Conclusion**: Based on the role of iodine in the production of thyroid hormones, which are essential for the metamorphosis of frog tadpoles, the correct answer is iodine.

**Final Answer**: The addition of **iodine** in water speeds up the metamorphosis in frog's tadpole larva.

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