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OG18官方指南,建议同学们刷3遍。第一遍做题了解题型和考点,第二遍精刷,第三遍集中解决疑难问题。建议考生第一遍刷题采用官方正版纸质书籍,若遇到疑难问题,欢迎在此专区查阅解析,提供解析,参与题目讨论,与所有考生一起解决疑难问题。
阅读RC-14289 (第3/6题) Time Cost00:00
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该题平均耗时:2m40s,平均正确率:53.3%

建议使用官方纸质指南,查看对照完整题目

A small number of the forest species of lepidoptera (moths and butterflies, which exist as caterpillars during most of their life cycle) exhibit regularly recurring patterns of population growth and decline—such fluctuations in population are known as population cycles. Although many different variables influence population levels, a regular pattern such as a population cycle seems to imply a dominant, driving force. Identification of that driving force, however, has proved surprisingly elusive despite considerable research. The common approach of studying causes of population cycles by measuring the mortality caused by different agents, such as predatory birds or parasites, has been unproductive in the case of lepidoptera. Moreover, population ecologists’ attempts to alter cycles by changing the caterpillars’ habitat and by reducing caterpillar populations have not succeeded. In short, the evidence implies that these insect populations, if not self-regulating, may at least be regulated by an agent more intimately connected with the insect than are predatory birds or parasites.

Recent work suggests that this agent may be a virus. For many years, viral disease had been reported in declining populations of caterpillars, but population ecologists had usually considered viral disease to have contributed to the decline once it was underway rather than to have initiated it. The recent work has been made possible by new techniques of molecular biology that allow viral DNA to be detected at low concentrations in the environment. Nuclear polyhedrosis viruses are hypothesized to be the driving force behind population cycles in lepidoptera in part because the viruses themselves follow an infectious cycle in which, if protected from direct sunlight, they may remain virulent for many years in the environment, embedded in durable crystals of polyhedrin protein. Once ingested by a caterpillar, the crystals dissolve, releasing the virus to infect the insect’s cells. Late in the course of the infection, millions of new virus particles are formed and enclosed in polyhedrin crystals. These crystals reenter the environment after the insect dies and decomposes, thus becoming available to infect other caterpillars.

One of the attractions of this hypothesis is its broad applicability. Remarkably, despite significant differences in habitat and behavior, many species of lepidoptera have population cycles of similar length, between eight and 11 years. Nuclear polyhedrosis viral infection is one factor these disparate species share.

【OG20-P431-535题】

Which of the following, if true, would most weaken the author's conclusion in highlight lines ?

  • 分析A选项
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  • 分析B选项
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  • 分析C选项
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  • 分析D选项
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  • 分析E选项
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该题目由网友yiLUvtiG提供。更多GMAT题目请
暂无雷哥网文字解析
当前版本由 你是风儿 更新于2015-11-17 17:49:43 感谢由 你是风儿 对此题目的解答所做出的贡献。

这是一道weaken削弱型的逻辑推理题,先从高亮的句子中找到原文推理的假设,从假设来着手,文章提到第一种方法的unproductive和第二种方法的not succeeded就直接得出由self-regulating或者other agent的结论,文章的假设是方法不成功就是里面猜猜的原因不对,而是其他原因引起,而没有考虑方法本身在实施过程中的不合理导致的不成功。

A选项:bird和parasite数量的减少对population cycle的影响原文并没有提到,只是实施了实验试图

测试这种影响

B选项:new experiemnt有了新的结论,untried way说明是对之前实验的改进,并且实验表明habit对population cycle有影响,自然就削弱了下文说有其他因素影响的说法

C选项:这个选项只是在混淆下文的nuclear polyhedrosis virus和第一段的结论,nuclear polydedrosis virus和birds,parasites都是population cycle的factor,两者的结合并不能在逻辑上证明结论的猜想是错的

D选项:实验条件的困难是方法不成功的原因之一,但是这个选项里有个隐含的错误逻辑,一但天气因素测起来简单,就能说明天气对population cycle有影响了吗?

E选项:病毒的多少对题目结论的猜测并没有影响


题目讨论 4条评论)

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  • 用户头像

    432442ba

    他因削弱吧
    0 0 回复 2019-10-06 23:31:00
  • 用户头像

    棋王

    变相考一道逻辑推理题,GMAT的套路太深
    0 0 回复 2019-09-01 20:58:17
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    小柴冲鸭

    文章的假设是方法不成功就是里面猜猜的原因不对,而是其他原因引起,而没有考虑方法本身在实施过程中的不合理导致的不成功。
    0 0 回复 2018-08-23 15:03:58
  • 用户头像

    Joyce L

    结论:these insect populations at least be regulated by other factor
    削弱:these insect populations are regulated by predatory birds or parasites.
    B:these insect populations are regulated by habitat change.
    
    habitat—predatory birds or parasites
    0 0 回复 2018-06-02 11:42:29
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