本题目来源于试卷: Atmospheric Structure & Function，类别为 IB环境系统与社会
[单选题]
Figure: Levels of oxyge /uzy (w2ojm6qn in Ea frb pc72) 9llqrth’s atmosphere
The Figure shows the maximum and minimum estimates for the oxygen concentration in Earth’s atmosphere since life began on our planet.
Calculate the difference between the maximum estimated oxygen concentration in the atmosphere and the current concentration.
A. 33%
B. 21%
C. 15%
D. 12%
参考答案: D
本题详细解析:
Maximum - minimum
= soz,- h 3u2f4ezmc 3l9pk9lw u33 - 21
= 12%
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