NEETZoologyBreathing and Exchange of Gases
Given below are two statements: one is labelled as Assertion (A) and the other is labelled as Reason (R). Assertion (A): The actual diffusion of O₂ and CO₂ between blood and atmospheric air occurs in the alveoli and their ducts. Reason (R): The part starting with the external nostrils up to the terminal bronchioles constitutes the conducting part of the respiratory system. In the light of the above statements, choose
Options
- ABoth (A) and (R) are correct and (R) is the correct explanation of (A)
- BBoth (A) and (R) are correct but (R) is not the correct explanation of (A)
- C(A) is correct but (R) is not correct
- D(A) is not correct but (R) is correct
Correct answer
B. Both (A) and (R) are correct but (R) is not the correct explanation of (A)
Step-by-step solution
Assertion (A) is correct because the alveoli and their ducts form the respiratory or exchange part of the respiratory system, which is the actual site of diffusion of O₂ and CO₂ between blood and atmospheric air. Reason (R) is correct because the conducting part of the respiratory system indeed extends from the external nostrils up to the terminal bronchioles. However, Reason (R) is not the correct explanation for Assertion (A). The alveoli act as the diffusion site due to their very thin squamous epithelium and ex