18. 恐龙灭绝和行星撞地球
Iridium, a hard, whitish metal similar to platinum, is extremely rare on Earth. Extremely high concentrations of iridium on Earth result from only two scenarios: massive volcanic eruptions that release iridium from deep within the Earth and meteorites that shower down on Earth from space. When scientists found concentrations of iridium 30 times higher than normal in rock stratum from 65 million years ago, they concluded that a massive meteor or comet hit the Earth and caused the massive extinction of the dinosaurs.
Which of the following, if true, most strongly supports the scientists conclusion?
A. Volcanoes massive enough to generate high concentrations of iridium are very rare.
B. Massive volcanic eruptions occurred frequently 80 million years ago.
C. Most scientists support the hypothesis that a cosmic impact wiped out the dinosaurs.
D. The massive extinction that occurred 70 million years ago killed not only the dinosaurs but also 70 percent of all life on Earth.
E. A comet struck the earth some 120 million years ago, but no widespread extinction occurred.
上一篇: GRE阅读和国外文化的联系
下一篇: GRE阅读关键字介绍分析
2016届高中英语必备单词知识点(素材)最后冲刺阶段易错词组背诵之二
Metonymy and synecdoche 修辞法:转喻和提喻
2016届高中英语必备单词知识点(素材)说标准的英语 读准音标是关键
2016届高中英语必备单词知识点(素材)英城市英语词汇
2016届高中英语必备单词知识点(素材)500多个高中英语重点词组总结
2016届高中英语短语知识点《Unit 3 The Million Pound Bank Note》学案 新人教版必修3
Got your number 我知道你打的什么算盘
2016届高中英语必备单词知识点(素材)it用法考点聚焦
2016届高三英语二轮复习【专题四】介词、连词与状语从句(精品教学案)
2016届高中英语必备单词知识点(素材)有些英语词汇,不能不懂装懂
2016届高中英语必备单词知识点(素材)阅读高频词组总结
2016届高中英语必备单词知识点(素材)高频单词词组总结
2016届高中英语短语知识点《Unit 1 Cultural Relics》学案 新人教版必修2
2016届高中英语必备单词知识点(素材)与中秋节相关的英语单词
2016届高中英语短语知识点《Unit 1 Friendship》学案 新人教版必修1
2016届高中英语必备单词知识点(素材)关于方位的英语单词
2016届高中英语必备单词知识点(素材)下册重点单词和短语知识点总结
2016届高考英语阅读改错提升训练32 经历感悟
2016届高中英语短语知识点《Unit 4 Astronomy the science of the stars》学案 新人教版必修3
2016届高三英语二轮复习【专题二】冠词和代词(精品教学案)
2016届高中英语必备单词知识点(素材)重点词汇短语总结大全(上)
2016届高中英语短语知识点《Unit 3 Travel journal》学案 新人教版必修1
2016届高中英语必备单词知识点(素材)重点词汇短语总结大全(下)
2016届高中英语短语知识点《Unit 1 Women of achievement》学案 新人教版必修4
2016届高三英语二轮复习【专题十】特殊句式与交际用语(精品教学案)
2016届高考英语阅读改错提升训练34 健康饮食(阅读理解)
2016届高中英语必备单词知识点(素材)动词make,break,bring,get知识点精讲
2016届高三英语二轮复习【专题一】名词和代词(精品教学案)
2016届高中英语短语知识点《Unit 3 Computers》学案 新人教版必修2
2016届高考英语阅读改错提升训练29 资讯报道