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): In the sequence of human respiration, the diffusion of O ₂ and CO ₂ between blood and tissues does not occur immediately after their diffusion across the alveolar membrane. Reason (R): Transport of gases by the blood acts as an essential intermediate step to carry O ₂ from the lungs to the systemic
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
A. Both (A) and (R) are correct and (R) is the correct explanation of (A)
Step-by-step solution
Respiration in humans involves a strict sequence of five steps. The first step is pulmonary ventilation, followed by the second step, which is the diffusion of gases across the alveolar membrane. The third step is the transport of gases by the blood. The fourth step is the diffusion of O ₂ and CO ₂ between blood and tissues, and the final step is cellular respiration. Assertion (A) is correct because the two distinct diffusion events (alveolar level and tissue level) are separated temporally and spatially by the tr