Question

Assertion :The birds can maintain a constant body temperature. Reason: Birds possess feathers covering their body.

• 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 B Both Assertion and Reason are correct but Reason is not the correct explanation for Assertion

Birds have a constant body temperature which commonly remains in between 104${}^0$ to 112${}^o$F, even in subzero weather. Thus they are called homoiothermal or warm-blooded. The feathers serve the most important function of retention of heat. Because the feathers form an efficient, non-conduction covering with its innumerable dead air spaces, they are useful in providing insulation. In cold weather, the heat loss is reduced to minimum by fluffing out the feathers, which increases the depth of insulating material by adding to the air spaces within the feathery layers. In warm weather, the feathers are often held close to the body to allow some escape of body heat.

So, the correct answer is B - 'Both Assertion and Reason are correct but Reason is not the correct explanation for Assertion'.