Question

Assertion: A tadpole deprived of a thyroid gland fails to metamorphose into an adult.
Reason: Thyroxine stimulates tissue differentiation and therefore affects the metamorphosis of tadpoles into an adult.

• A. If both Assertion and Reason are correct and Reason is the correct explanation of Assertion.
• B. If both Assertion and Reason are correct but the Reason is not the correct explanation of Assertion.
• C. If Assertion is correct but Reason is incorrect.
• D. If Assertion is incorrect but Reason is correct.

Answer 1

The correct option is B

If both Assertion and Reason are correct but the Reason is not the correct explanation of Assertion.

The correct option is (B):

Explanation of the assertion statement:

1. Metamorphosis can be defined as the change in physical and structural form from the larval stage to the adult stage.
2. The larval stage of frogs is known as tadpoles which consist of tails, they metamorphose to form adult frogs without tails.
3. The hormone thyroxine is responsible for the metamorphosis of tadpoles into adult frogs
4. Iodine is an important component for the production of thyroxine.
5. Due to the lack of iodine in the external environment, the tadpole may not metamorphose to form adult frogs.

Explanation of the reason statement:

1. Thyroxine hormone stimulates tissue differentiation and therefore affects the metamorphosis of a tadpole into an adult.
2. But for the production of thyroxine iodine is necessary.

Final answer:

If both Assertion and Reason are correct but the Reason is not the correct explanation of Assertion.