Question

How can a tadpole be prevented to change into frog for long time?

• A. By giving very less food
• B. By giving fat-rich food
• C. By adding lot of thyroxine to the water in which they are kept
• D. Provide them an antithyroid substance like thiourea.

Answer 1

The correct option is D Provide them an antithyroid substance like thiourea.

During metamorphosis, a tadpole is changed into the frog due to the over secretion of thyroxine hormone. But in the presence of antithyroid substance like thiourea, metamorphosis is stopped. The antithyroid drug acts antagonistically upon over reactive thyroid gland and reduces the secretion of thyroxine hormone which prevents the metamorphosis in the frog.