Question

Assertion :In a tadpole, if thyroid is cut, metamorphosis stops.
Reason: TSH is not secreted.

• A. Both Assertion and Reason are correct and Reason is the correct explanation for Assertion
• B. Both Assertion and Reason are correct but Reason is not the correct explanation for Assertion
• C. Assertion is correct but Reason is incorrect
• D. Both Assertion and Reason are incorrect

Answer 1

The correct option is C Assertion is correct but Reason is incorrect

In frogs, growth and metamorphosis (development of frog from tadpole stage to adult stage) is regulated by thyroxine gland. Thyroxine is secreted from thyroid gland. It stimulates the consumption of oxygen by metabolically active tissues and also increases the oxidation of glucose in tissues. Therefore, if thyroid is cut in a tadpole, metamorphosis will stop. Hence, assertion is correct.

TSH (Thyroid stimulating hormone) is secreted from anterior pituitary. It stimulates the release of thyroxine hormone from thyroid gland. Hence, reason is incorrect because in the tadpole whose thyroid gland has been removed, TSH will be secreted.

Thus, assertion is correct but reason is incorrect.

So, the correct answer is 'Assertion is correct but Reason is incorrect'.