文勇的新托福黄金&ccedil

Breedinggroundsin

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Unformatted text preview: res [█] that indicate where the following sentence could be added to the passage . In general, it is believed that these two extinctions resulted from drastic environmental changes that followed meteorite impacts or massive volcanic eruptions. Where would the sentence best fit? 14. Directions: An introductory sentence for a brief summary of the passage is provided below. Complete the summary by selecting the THREE answer choices that express the most important ideas in the passage. Some sentences do not belong in the summary because they express ideas that are not presented in the passage or are minor ideas in the passage. This question is worth 2 points. There have been many attempts to explain the causes of mass extinctions. ● ● ● Answer Choices ○Asteroid impacts, evolutionary developments, and changes in Earth' s climate and in the positions of the continents have all been proposed as possible causes of mass extinctions. ○Researchers have observed 26­million­year cycles in extinction rates of a number of fossil groups that could all be attributed to the same cause. ○According to the Alvarez hypothesis, much of the iridium originally present on Earth was thrown into the atmosphere as a result of an asteroid impact that also caused a mass extinction. ○The unusual distribution of iridium on Earth and the presence of craters and heat­shocked quartz are central to the theory that an asteroid impact caused the late Cretaceous event. ○The collision between Earth and a large asteroid resulted in massive damage and generated enough heat to cause irreversible changes in Earth' s atmosphere. ○There was a particularly large mass extinction that occurred around 250 million years ago at the end of the Permian period, whose cause could not be determined. 在在在在在 1. ○3 2. ○1 420 [email protected] 在在在在在在 www.liuwenyong.com 在在在在在在在在在在在在在在在,在在在在在在在在在在 3. ○4 4. ○3 5. ○4 6. ○1 7. ○2 8.○3 9. ○2 10. ○1 11. ○4 12. ○3 13. ○4 14. ○1, 2, 4 421 [email protected] 在在在在在在 www.liuwenyong.com 在在在在在在在在在在在在在在在,在在在在在在在在在在 在在在在 在在在在在在在 在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在 在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在 在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在 在在在在在...
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This note was uploaded on 09/17/2013 for the course LANGUAGE 13DL208 taught by Professor Wang during the Fall '13 term at East China Normal University.

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