Q40:

Two centuries ago, Tufe Peninsula became separated form the mainland, isolating on the newly formed Tufe Island a population of Turfil sunflowers. This population’s descendants grow to be, on average, 40 centimeters shorter than Turfil sunflowers found on the mainland. Tufe Island is significantly drier than Tufe Peninsula was. So the current average height of Tufe’s Turfil sunflowers is undoubtedly at least partially attributable to changes in Tufe’s environmental conditions.

Which of the following is an assumption on which the argument depends?

There are no types of vegetation on Tufe Island that are known to benefit from dry conditions. There were about as many Turfil sunflowers on Tufe Peninsula two centuries ago as there are on Tufe Island today. The mainland’s environment has not changed in ways that have resulted in Turfil sunflowers on the mainland growing to be 40 centimeters taller than they did two centuries ago. The soil on Tufe Island, unlike that on the mainland, lacks important nutrients that help Turfil sunflowers survive and grow tall in a dry environment. The 40-centimeter height difference between the Turfil sunflowers on Tufe Island and those on the mainland is the only difference between the two populations.

答案是C.我选的是D.

谁能告诉我题目说的是什么意思呀. 为什么选C呢? 谢谢

高度相差有两种原因

一是大陆上的植物长高了，岛上的没有变。另外一种是岛上的植物变矮了，而大陆上的没有变化

按原文的解释，当然要在前提上就排除第一种咯。否则第二种怎么会站的住脚呢

你再想想看，不会很难理解的

和该套题中的32题一样，都是假设前提条件一致，

200年前岛屿分化分离之前，两个地方的条件是一样的，从而排除了他因导致sunflower变得更矮小，进一步说明确实是分离后岛屿的环境改变才导致这种高度不一的