Question

Tadpoles of frog can be made to grow as giant sized tadpoles, if they are

• A. Administered anti-thyroid substance like thiourea.
• B. Administered large amounts of thyroxine.
• C. Reared on a diet rich in egg yolk.
• D. Reared on a diet rich in both egg yolk and glucose.

Answer 1

The correct option is A Administered anti-thyroid substance like thiourea.

Xenopus laevis tadpoles that arrest development and remain as larvae for several years sometimes occur spontaneously in laboratory populations. These tadpoles cease development at an early hindlimb stage, but continue to grow and develop into grossly deformed giants. Giant tadpoles lack thyroid glands, and differ in morphology and behaviour from normal larvae. Tadpoles of frog can be made to grow as giant sized tadpoles, if they are administered large amounts of thryoxine.