Question

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

• A. Maintain them on very little food.
• B. Provide them with diet rich in proteins.
• C. Add lot of thyroxin to the aqueous medium in which they are kept.
• D. Provide them an antithyroid substance like thiourea.

Answer 1

Answer: (D)

Provide them an antithyroid substance like thiourea.

Tadpoles undergo metamorphosis to form frogs. Metamorphic failure can be caused by a lack of thyroid stimulating hormone, which is used to induce the thyroid to produce thyroxine in transforming the tadpoles. If the tadpole is provided with an antithyroid substance (like thiourea), they will stop metamorphosis and cannot be transformed into bigger adults (frogs).
Thus, the correct answer is option (D), 'Provide them an antithyroid substance like thiourea'.