63篇第29篇第5题 谢谢！

AmyGMAT

第五题我选的A 答案选E 哪位nn能帮忙解释一下？谢谢！这是一篇立论型文章。作者阐明一个自己提出的观点，理论，解释，没有对立面。这类文章重点关注作者自己观点的论证过程。这类文章一般没有作者的评价性内容
Passage 29 (29/63) 专业性科学文章Studies of the Weddell seal in thelaboratory have described the physiological mechanisms that allow the seal tocope with the extreme oxygen deprivation that occurs during its longest dives,which can extend 500 meters below the ocean’s surface and last for over 70minutes.（ Recent field studies, however,suggest that during more typical dives in the wild, this seal’s physiologicalbehavior is different. ）新观点  新老观点对比型
老观点Inthe laboratory,（ when the seal divesbelow the surface of the water and stops breathing, its heart beats moreslowly, requiring less oxygen, and its arteries become constricted, ensuringthat the seal’s blood remains concentrated near those organs most crucial toits ability to navigate underwater. The seal essentially shuts off the flow ofblood to other organs, which either stop functioning until the seal surfaces orswitch to an anaerobic (oxygen-independent) metabolism. The latter results in the production of large amounts of lactic acid (lactic acid: n.乳酸) which can adversely affect the pHof the seal’s blood, butsince3* the anaerobic metabolism occurs only in those tissues which havebeen isolated from the seal’s blood supply, the lactic acid is released intothe seal’s blood only after the seal surfaces, when the lungs, liver, and otherorgans quickly clear the acid from the seal’s bloodstream.）因为是专业型文章一般来说看记不住，因此这里快速略读。
新观点Recentfield studies, however,reveal that on dives in the wild, the seal usually heads directly for its preyand returns to the surface in less than twenty minutes. （The absenceof high levels of lactic acid in the seal’s blood after such dives suggeststhat during them, the seal’s organs do not resort to the anaerobic metabolismobserved in the laboratory, but are supplied with oxygen from the blood. Theseal’s longer excursions underwater, during which it appears to be eitherexploring distant routes or evading a predator, do evoke the diving responseseen in the laboratory. ）略读。因为内容较复杂，做题时回来定位。But（转折，要注意，下面的仔细读） why do the seal’s laboratorydives always evoke this response, regardless of their length or depth? Somebiologists speculate that because in laboratory dives the seal is forciblysubmerged, it does not know how long it will remain underwater and so prepares for the worst.
1.    Thepassage provides information to support which of thefollowing generalizations?较难的信息定位题，每一个选项都要定位。
(A) Observations of animals’ physiologicalbehavior in the wild are not reliable unless verified 证实by laboratory studies. 错
(B) It is generally less difficult toobserve the physiological behavior of an animal in the wild than in the laboratory.没提过
(C) The level of lacticacid in an animal’s blood is likely to be higher when it is searchingfor prey than when it is evading predators.利用这三点小信息定位。
(D) The level of lactic acid in an animal’sblood is likely to be lowest during those periods in which it experiencesoxygen deprivation. 错（E）
(E) The physiological behavior of animalsin a laboratory setting is not always consistent with their physiologicalbehavior in the wild. 正确 根据主旨即可得
2.    推断题It can be inferred from thepassage that by describing the Weddell seal as preparing “for the worst” (line41), biologists mean that it
(A) prepares to remain underwater for nolonger than twenty minutes
(B) exhibits physiological behavior similarto that which characterizes dives in which it heads directly for its prey
(C) exhibits physiological behavior similarto that which characterizes its longest dives in the wild正确
(D) begins to exhibit predatory behavior（C）
(E) clears the lactic acid from its bloodbefore attempting to dive
3.    Thepassage suggests that during laboratory dives, the pH ofthe Weddell seal’s blood is not adverselyaffected by the production of lactic acidbecause 事实信息定位题
(A) only those organs that are essential tothe seal’s ability to navigate underwater revert to an anaerobic mechanism
(B) the seal typically reverts to ananaerobic metabolism only at the very end of the dive
(C) organs that revert to an anaerobicmetabolism are temporarily isolated from the seal’s bloodstream正确
(D) oxygen continues to be supplied toorgans that clear lactic acid from the seal’s bloodstream（C）
(E) the seal remains submerged for onlyshort periods of time
4.    Which ofthe following best summarizes the main point of the passage?主旨题
(A) Recent fieldstudies have indicated that descriptions of the physiological behavior of theWeddell seal during laboratory dives are not applicable to its most typicaldives in the wild.正确
新旧观点对比型文章，主题出现在新观点出现之处。
(B) The Weddell seal has developed a numberof unique mechanisms that enable it to remain submerged at depths of up to 500meters for up to 70 minutes.
(C) The results of recent field studieshave made it necessary for biologists to revise previous perceptions of how theWeddell seal behaves physiologically during its longest dives in the wild.
(D) Biologists speculate that laboratorystudies of the physiological behavior of seals during dives lasting more thantwenty minutes would be more accurate if the seals were not forcibly submerged.（A）
(E) How the Weddell seal responds to oxygendeprivation during its longest dives appears to depend on whether the seal issearching for prey or avoiding predators during such dives.
5.    Accordingto the author, which of the following is true of thelaboratory studies mentioned in line 1?（此题狡猾！）
(A) They fail to explain how the seal isable to tolerate the increased production of lactic acid by organs that revertto an anaerobic metabolism during its longest dives in the wild.
(B) They present an oversimplified accountof mechanisms that the Weddell seal relies on during its longest dives in thewild.
(C) They provide evidence that underminesthe view that the Weddell seal relies on an anaerobic metabolism during itsmost typical dives in the wild.
(D) They are based on the assumption thatWeddell seals rarely spend more than twenty minutes underwater on a typicaldive in the wild.（E）
(E) They provide an accurate account of thephysiological behavior of Weddell seals during those dives in the wild in whichthey are either evading predators or exploring distant routes.
6.    The authorcites which of the following as characteristic of the Weddell seal’sphysiological behavior during dives observed in the laboratory?
I.    A decrease inthe rate at which the seal’s heart beats
II.   A constrictionof the seal’s arteries
III.  A decrease inthe levels of lactic acid in the seal’s blood
IV.   A temporary haltin the functioning of certain organs
(A) I and III only
(B) II and IV only
(C) II and III only
(D) I, II, and IV only（D）
(E) I, III, and IV only
7.    Thepassage suggests that because Weddell seals are forcibly submerged duringlaboratory dives, they do which of the following?
(A) Exhibit the physiological responsesthat are characteristic of dives in the wild that last less than twentyminutes.
(B) Exhibit the physiological responsesthat are characteristic of the longer dives they undertake in the wild.正确
(C) Cope with oxygen deprivation lesseffectively than they do on typical dives in the wild.
(D) Produce smaller amounts of lactic acidthan they do on typical dives in the wild.（B）
(E) Navigate less effectively than they doon typical dives in the wild.

草稿纸

(A) They fail to explain how the seal isable to tolerate the increased production of lactic acid by organs that revertto an anaerobic metabolism during its longest dives in the wild.


正是你略读的部分：

The latter results in the production of large amounts of lactic acid (lactic acid: n.乳酸) which can adversely affect the pHof the seal’s blood, butsince3* the anaerobic metabolism occurs only in those tissues which havebeen isolated from the seal’s blood supply, the lactic acid is released intothe seal’s blood only after the seal surfaces, when the lungs, liver, and otherorgans quickly clear the acid from the seal’s bloodstream.）因为是专业型文章一般来说看记不住，因此这里快速略读。

第一行的科学家在实验环境下已经解释清楚了所有的长时间潜水的道理，只是忽略了野外捕食的情况。

ffen

The seal essentially shuts off the flow of blood to other organs, which either stop functioning until the seal surfaces or switch to an anaerobic (oxygen-independent) metabolism. The latter results in the production of large amounts of lactic acid which can adversely affect the pH of the seal’s blood, but since the anaerobic metabolism occurs only in those tissues which have been isolated from the seal’s blood supply, the lactic acid is released into the seal’s blood only after the seal surfaces, when the lungs, liver, and other organs quickly clear the acid from the seal’s bloodstream.

3.    The passage suggests that during laboratory dives, the pH of the Weddell seal’s blood is not adversely affected by the production of lactic acid because （D）正确答案是C
(A) only those organs that are essential to the seal’s ability to navigate underwater revert to an anaerobic mechanism
(B) the seal typically reverts to an anaerobic metabolism only at the very end of the dive
(C) organs that revert to an anaerobic metabolism are temporarily isolated from the seal’s bloodstream
(D) oxygen continues to be supplied to organs that clear lactic acid from the seal’s bloodstream
(E) the seal remains submerged for only short periods of time

定位准确了，但是好像内部的逻辑关系理不顺了，以至于第3题错了。。。求解释呀！小女子先谢过了～

mofell

这个动物先停止通往其他器官的血流..这会导致 2个结果：
1这个器官stop functioning 直到它回到水面了
2.这些器官转成无氧呼吸

第二种情况会导致乳酸增加，乳酸的增加会adversely affect PH（就是使它降低）
但事实上，第二种情况只发生在那些远离血液供应的器官
所以在seal回到水面后 乳酸才真正释放到血液里
而这个时候，那些 lungs, liver, and other organs 就能很快把乳酸清理掉

问题问的是during laboratory dives, the pH of the Weddell seal’s blood is not adversely affected by the production of lactic acid
所以原因是  organs that revert to an anaerobic metabolism are temporarily isolated from the seal’s bloodstream

mofell

这个动物先停止通往其他器官的血流..这会导致 2个结果：
1这个器官stop functioning 直到它回到水面了
2.这些器官转成无氧呼吸

第二种情况会导致乳酸增加，乳酸的增加会adversely affect PH（就是使它降低）
但事实上，第二种情况只发生在那些远离血液供应的器官
所以在seal回到水面后 乳酸才真正释放到血液里
而这个时候，那些 lungs, liver, and other organs 就能很快把乳酸清理掉

问题问的是during laboratory dives, the pH of the Weddell seal’s blood is not adversely affected by the production of lactic acid
所以原因是  organs that revert to an anaerobic metabolism are temporarily isolated from the seal’s bloodstream

poorcat

恩恩 同谢谢啦