《The Cambrian Explosion》这篇文章最后一题，总觉得答案不对，或者是我有想错了，急请大牛帮解释下~~感激不尽
1. 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 answer choices 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.
The term “Cambrian explosion” refers to the geologically brief period during which all modern animal groups evolved.
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Answer Choices
○Little is known about the stages of evolution during the Cambrian period, in part because early animals were soft bodied and could fossilize only under particular conditions. 问题、困难的提出
○While animal fossils from before the Cambrian explosion have no modern descendants, many animals that evolved during the Cambrian explosion can be assigned to modern groups.
○The Cambrian period is significant because it marks the emergence of eukaryotic life-forms – organisms that have cells with true nuclei 错误
○The Ediacara fossil formation provides the most information about the Cambrian explosion, while the earlier, Tommotian and Burgess Shale formations give clues about Precambrian evolution. 概述三种化石的发现
○Zoologists are awaiting the discovery of a 600-million-year-old fossil formation in order to be able to form a theory of how animal evolution progressed.
细枝末节
○Although the reasons for the rapid evolution of animals during the Cambrian period are not known, one proposed explanation is an abundance of niches with a lack of competitors
. 猜想，解决方案作者: 苇叶笛声 时间: 2011-8-3 17:31:48
问题、困难的提出
错误
概述三种化石的发现
猜想，解决方案