Question

For the metamorphosis of tadpoles which of the following elements must be available in the water?

• A. Chlorine
• B. Carbon
• C. Sulphur
• D. Iodine

Answer 1

The correct option is D

Iodine

The correct option is D.

Explanations of correct option:

Option D:

1. Metamorphosis is a developmental process where after birth an organism undergoes physical and structural changes to modify itself to reach a successive stage of its life cycle.
2. It is found in various insects, like butterflies tadpoles, amphibians, etc.
3. Iodine is one of the essential elements required in the process of metamorphosis, which helps in the synthesis of thyroid hormone.
4. Thyroid hormone controls the metabolism and developmental processes of a body, hence it is essential for growth.
5. For example, the eggs of a frog grow into a tadpole which later develops into a mature frog.
6. The successive steps involving the changes in the life cycle of a frog to reach into a mature frog are known as metamorphism.

Explanations of incorrect options:

Option A:

1. Chlorine is an inorganic element.
2. It is toxic and irritating for the eyes.
3. Chlorine does not help in the metamorphosis of tadpoles.

Option B:

1. Carbon is an omnipresent element.
2. It is a major of organic molecules.
3. Chlorine does not help in the metamorphosis of tadpoles.

Option C:

1. Sulfur is a major part of proteins containing sulfur groups.
2. It is insoluble in water.
3. Sulfur does not help in the metamorphosis of tadpoles.

Final answer: For the metamorphosis of tadpoles Iodine must be available in the water.