题目内容双击单词支持查询和收藏哦～

收藏纠错

题目材料：

When Earth formed 4.6 billion years ago, the Sun burned only 70 percent as brightly as it does today. Yet Geologic record contains no evidence for widespread glaciation until 2.3 billion years ago. Sagan and Mullen suggested in the 1970s that ammonia, a greenhouse gas, warmed early Earth`s atmosphere, but subsequent research showed that the Sun`s ultraviolet rays rapidly destroy ammonia in an oxygen-free environment, such as that of early Earth. Many scientists now attribute much of the warming of early Earth to oxygen-intolerant microbes-methanogens-that produce the greenhouse gas methane.The methanogen hypothesis could help to explain the first global ice age: 2.3 billion years ago, Earth`s atmosphere began to fill with oxygen produced by other microbes-cyanobacteria-causing methanogens to decline rapidly.

Which of the following can be inferred from the passage about methanogens?

A.Methanogens must have appeared on Earth later than 2.3 billion years ago.
B.Methanogens must have been much more prevalent in some regions of the early Earth than in others.
C.Methanogens produce a greenhouse gas that is more susceptible to destruction by the Sun's ultraviolent rays than is ammonia.
D.Methanogens could not have thrived in early Earth's atmosphere without the presence of ammonia.
E.Methanogens would have had a less significant effect on early Earth's atmosphere if they had evolved after the appearance of cyanobacteria.

E显示答案

登录后才可以添加做题笔记哦，还没有账号？马上注册

· 相关考点

推断题

以上解析由考满分老师提供。

题目讨论

已经输入 0 个字标记为提问，会有更多小伙伴帮你解答提交

全部讨论

只看提问

按时间排序

按点赞数排序

拓展练习

练习记录

最新提问

题目内容双击单词支持查询和收藏哦～

题目讨论