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]
Identify which of the following is notec qmg*0 ;x0fm tr /.dwhvlh ;2ahue about atmospheric carbon dioxide levels over the last 4 billion years.2hh/awv;h .dl
I.
They have fluctuated (moved up and down).
II.
They have been constantly increasing overall.
III.
They have never been higher than they are today.
IV.
They have influenced the temperature of the Earth.
A. II and III only
B. I and III only
C. II only
D. I, II and III
参考答案: A
本题详细解析:
Statement I is true, statement II is not true as there has been an overall mxyccfvndfzu(1 1ea7d9(w 6 9decrease over that time. Statement III is not true as it is quite low compared to many timed ca19 7 xzdcyf(1w9uv(6n fmes in the past. Statement IV is true. Therefore, option A is the correct choice
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