O-LevelBiologyRespiration5090/11 · May/June 2025 · Q141 Mark
The percentages of each of the gases in inspired and expired air are measured when a student is resting and when a student is exercising. The results are shown. From the data, which statement about active transport is not correct?
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AThe difference between the percentages of carbon dioxide in expired air when exercising and in expired air when resting is 1.5.
BWhen resting, the difference between the percentage of oxygen in inspired and expired air is due to oxygen being used by respiration in the body.
CInspired air contains 52.5 times more oxygen than carbon dioxide.
DThe percentage of oxygen taken from inspired air is the same as the percentage of carbon dioxide added to expired air when exercising.
✓ Correct answer
C: Inspired air contains 52.5 times more oxygen than carbon dioxide.
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