[請益] TPO 15 MASS EXTINCTIONS 最後一題

看板TOEFL_iBT (TOEFL_iBT托福)作者jasonfghx (工人)時間12年前 (2013/10/09 20:54)推噓0(0推 0噓 3→)

留言3則, 1人參與討論串1/1

14.Answer Choices: ○1. 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. ○2. Researchers have observed 26-million-year cycles in extinction rates of a number of fossil groups that could all be attributed to the same cause. ○3. 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. ○4. The unusual distribution of iridium on Earth and the presence of craters and heat-shocked quartz are central to the theory that an asteroid impact caused the late Cretaceous event. ○5. The collision between Earth and a large asteroid resulted in massive damage and generated enough heat to cause irreversible changes in Earth's atmosphere. ○6. 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. 正確答案是1,2,4 想問第二選項一直很困擾我 Researchers have observed 26-million-year cycles in extinction rates of a number of fossil groups that could all be attributed to the same cause. 這邊講到the same cause 該段也沒說倒是發生於同一原因這個同一個原因是第四段後面討論的a companion star? 謝謝回復 -- ※ 發信站: 批踢踢實業坊(ptt.cc) ◆ From: 140.116.73.176