OG 43-261

OWEN0410

Homeostasis, an animal’s maintenance of certain internal variables within an acceptable range, particularly in extreme physical environments, has long interested biologists. The desert rat and the camel in the most water-deprived environments, and marine vertebrates in an all-water environment, encounter the same regulatory problem: maintaining adequate internal fluid balance.

For desert rats and camels, the problem is conservation of water in an environment where standing water is nonexistent, temperature is high, and humidity is low. Despite these handicaps, desert rats are able to maintain the osmotic pressure of their blood, as well as their total body-water content, at approximately the same levels as other rats. One countermeasure is behavioral: these rats stay in burrows during the hot part of the day, thus avoiding loss of fluid through panting or sweating, which are regulatory mechanisms for maintaining internal body temperature by evaporative cooling (evaporative cooling: 蒸发冷却). Also, desert rats’ kidneys can excrete a urine having twice as high a salt content as sea water.

Camels, on the other hand, rely more on simple endurance. They cannot store water, and their reliance on an entirely unexceptional kidney results in a rate of water loss through renal function significantly higher than that of desert rats. As a result, camels must tolerate losses in body water of up to thirty percent of their body weight. Nevertheless, camels do rely on a special mechanism to keep water loss within a tolerable range: by seating and panting only when their body temperature exceeds that which would kill a human, they conserve internal water.

Marine vertebrates experience difficulty with their water balance because though there is no shortage of seawater to drink, they must drink a lot of it to maintain their internal fluid balance. But the excess salts from the seawater must be discharged somehow, and the kidneys of most marine vertebrates are unable to excrete a urine in which the salts are more concentrated than in seawater. Most of these animals have special salt-secreting organs outside the kidney that enable them to eliminate excess salt.

261. Which of the following most accurately states the purpose of the passage?

(A) To compare two different approaches to the study of homeostasis

(B) To summarize the findings of several studies regarding organisms’ maintenance of internal variables in extreme environments

(C) To argue for a particular hypothesis regarding various organisms’ conservation of water in desert environments

(D) To cite examples of how homeostasis is achieved by various organisms（D）

(E) To defend a new theory regarding the maintenance of adequate fluid balance

我想请问B,答案说B is incorrect because no partjicular studies are cited in the passage

到底什么才算是study呢？.

OWEN0410

晕，每人里我！！

追逐梦想2006

总结第二遍时，发现同样的问题，顶，哪位牛人能倾囊相授？为什么og解释说：B is incorrect because no partjicular studies are cited in the passage

B为什么错？？？

追逐梦想2006

把og的解释贴全，先

This question asks you to identify the primary concern of the passage. The best answer is D. The

passage focuses primarily on a discussion of how various animals achieve homeostasis. Choice A

is not correct: while the passage does discuss the regulatory mechanisms employed by animals in

two very different environments, it does not compare two different approaches to the study of

those mechanisms. Choice B is not correct because no particular studies are cited in the passage.

Choices C and E can be eliminated because the passage is concerned with a straightforward

description of certain regulatory processes in various animals. It does not argue in favor of any

particular hypothesis, nor does it defend any new theory concerning homeostasis.

追逐梦想2006

先说说自己的理解：

（1）B错，summarize 表示总结，对应的套路应该在文末有一个总结的陈词，而原文没有；finding of study，一定要文中明确讲明科学家开展了三个study，研究的结果表明了...，而原文是先说了结论，再引例证，所以B错误

（2）E正确，examples正确，of how homeostasis is achieved 是文章的主题。

请问牛牛，理解是否正确？

wangyu73cn

以下是引用追逐梦想2006在2006-1-13 1:24:00的发言：

先说说自己的理解：

（1）B错，summarize 表示总结，对应的套路应该在文末有一个总结的陈词，而原文没有；finding of study，一定要文中明确讲明科学家开展了三个study，研究的结果表明了...，而原文是先说了结论，再引例证，所以B错误

（2）E正确，examples正确，of how homeostasis is achieved 是文章的主题。

请问牛牛，理解是否正确？

对于第（2）点，同意。D正确。你可能笔误，写成E了。

对于第（1）点，我认为summarize的套路，不一定要在文末进行总结。所以前办个判据不太充分。对于后半的意见。基本同意。也就是应该认真考虑一下什么叫study。需要精确，不能含糊，不能把实例和科学研究两者混淆。