Tadpoles can be made to grow in size and become adult by

• Correct answer
  A

  injecting thyroxine hormone
• B

  feeding the eggs of other frogs
• C

  injecting gonadotrophic hormones
• D

  providing them with suitable climatic conditions.

Solution

Tadpoles can be made to grow in size and become adult by injecting thyroxine hormone. The process by which tadpole grows in size and becomes adult is known as metamorphosis. The amphibian metamorphosis is under neuroendocrine control.

Hence, the correct answer is option: 'A'.