How can one keep a tadpole of frog unchanged in the same stage for a pretty long time?

Options

A. Maintain them on very little food
B. Provide a diet rich in proteins
C. Add lot of thyroxine to the aqueous medium
D. Provide them an antithyroid substance like thiourea.

Answer

To keep a tadpole of a frog unchanged in the same stage for a prolonged period, follow these steps:

### Step-by-Step Solution:

1. **Understand Metamorphosis**:
- Metamorphosis is the biological process where a tadpole transforms into an adult frog. This process is primarily regulated by thyroid hormones, particularly thyroxine.

2. **Identify the Role of Thyroid Hormones**:
- Thyroid hormones trigger the metamorphosis process. When these hormones are present in high amounts, the tadpole undergoes changes to become an adult frog.

3. **Reduce Thyroid Hormone Levels**:
- To prevent the transformation, it is essential to reduce the levels of thyroid hormones. This can be achieved by using anti-thyroid substances.

4. **Use Anti-Thyroid Substances**:
- One effective anti-thyroid substance is Thyrouria. This compound inhibits the production of thyroxine, thereby halting the metamorphosis process.

5. **Maintain Environmental Conditions**:
- Ensure that the tadpole is kept in an environment where the levels of thyroxine are low. This can involve controlling the water conditions and avoiding any substances that might stimulate hormone production.

6. **Monitor Diet**:
- While the diet can influence growth, it is crucial to provide a diet that does not promote metamorphosis. A diet low in protein can be beneficial, as protein-rich diets may encourage growth and development.

### Conclusion:
By using anti-thyroid substances like Thyrouria and maintaining appropriate environmental conditions, one can keep a tadpole unchanged in the same stage for an extended period.

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