alleryStart learning →Fresh air is 21 percent oxygen, exhaled air about 15. Why the drop?
AMucus destroys the oxygen
BOxygen turns into nitrogen
CLungs store it forever
DCells use it in respiration
Answer & Solution
Correct answer: D. Cells use it in respiration
Part of the oxygen passes into blood and is consumed by cells in respiration, so less is left in exhaled air.
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