[Campbell Biology P.999] Based on the text, which of the following statements about breathin... | Practice Question

Based on the text, which of the following statements about breathing mechanisms in vertebrates is correct?

  • A: Mammals ventilate their lungs using positive pressure, similar to amphibians.
  • B: Birds use air sacs to ensure unidirectional airflow through their lungs.
  • C: Amphibians primarily rely on negative pressure breathing for gas exchange.
  • D: The efficiency of ventilation in mammals is increased due to the mixing of incoming and outgoing air.

Explanation

The text states that 'Birds use a system of air sacs as bellows to keep air flowing through the lungs in one direction only, preventing the mixing of incoming and outgoing air.' This directly supports option B. Mammals use negative pressure breathing, and this process leads to mixing of air, which decreases efficiency, contrary to options A and D. Amphibians use positive pressure breathing, making option C incorrect.