Question

Which one of the following statements is incorrect?

• A. The residual air in lungs slightly decreases the efficiency of respiration in mammals
• B. The presence of non-respiratory air sacs, increases the efficiency of respiration in birds
• C. In insects, circulating body fluids serve to distribute oxygen to tissues
• D. The principle of countercurrent flow facilitates efficient respiration in gills of fishes

Answer 1

Answer: (A)

The residual air in lungs slightly decreases the efficiency of respiration in mammals

Answer 2

The presence of non-respiratory air sacs increases the efficiency of respiration in birds. In birds, respiratory air sacs are actually non-expanding and function as bellows to maintain a unidirectional flow of air through the lungs, but they do not directly participate in gas exchange.

So, the correct option is (A): The residual air in lungs slightly decreases the efficiency of respiration in mammals