For the metamorphosis of tadpoles which of the following elements must be available in water? (a) chlorine (b) carbon (c) sulphur iodine

• Soln:

Answer is (d) iodine

Explanation:

Metamorphosis is brought by a hormone called as thyroxine. Thyroid gland needs Iodine to secrete Thyroxine. Hence Iodine should be present in water for the metamorphosis of tadpoles.