Question 27
EasyOriginal questionAbout what percentage of the air, by volume, is oxygen?
Show the answer and explanation
CorrectNot quiteAnswer B
Correct answer: B
Explanation
Oxygen makes up about 21% of dry air; it is constantly renewed by photosynthesis.
Worth noting
0.04% is carbon dioxide and 78% is nitrogen.
- Concept
- Oxygen in the air
- Typical timeTypical
- 35 s
- Your timeYours
- —
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