Scientists formerly believed that the rocky planets—Earth, mercury, Venus, and Mars—were created by the rapid gravitational collapse of a dust cloud, a deflation giving rise to a dense orb. That view was challenged in the 1960s, when studies of Moon craters revealed that these craters were caused by the impact of objects that were in great abundance about 4.5 billion years ago but whose number appeared to have quickly decreased shortly thereafter. This observation rejuvenated Otto Schmidt’s 1994 theory of accretion. According to this theory, cosmic dust gradually lumped into ever- larger conglomerates: particulates, gravel, small and then larger balls, planetesimal (tiny planets), and ultimately, planets. As the planetesimals became larger, their numbers decreased. Consequently, the number of collisions between planetesimals decreased.
Consider each of the choices separately and select all that apply.
19. The passage provides evidence that Schmidt would be likely to disagree with the theory presented in the first sentence over
(A) the length of time it took for the rocky planets to form.
(B) the most likely causes of the Moon’s impact craters.
(C) the importance cosmic dust as a seminal material in planetary formation.
而且从文章意思上来看,crater(环形山)和碰撞是有关的,因为“the number of collisions between planetesimals decreased”, 所以“craters were caused by the impact of objects that were in great abundance about 4.5 billion years ago but whose number appeared to have quickly decreased shortly thereafter”
后面的信息我觉得没问题,但我认为都不是第一句的collapse的相关信息。
由于题干中“disagree with the theory presented in the first sentence over”,强调了第一句中的理论,第一句的理论很简单,就是“the rapid gravitational collapse of a dust cloud”,无法知晓任何关于crater的信息。