2. 外语
  3. Although many hypotheses have been proposed to explain why some plant communities are more susceptible than others to invasion b

Although many hypotheses have been proposed to explain why some plant communities are more susceptible than others to invasion b

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问题     Although many hypotheses have been proposed to explain why some plant communities are more susceptible than others to invasion by nonnative species, results from field studies have been inconsistent and no general theory of invasibility has yet emerged. However, a theory based on fluctuating resource availability could integrate most existing hypotheses and successfully resolve many of the apparently conflicting and ambiguous results of previous studies. The suggested theory is that a plant community becomes more susceptible to invasion whenever there is an increase in the amount of unused resources.
    The diversity in the range of resource-release mechanisms could partly explain the absence of consistent ecological correlates of invasibility. In particular, the theory predicts that there will be no necessary relationship between the species diversity of a plant community and its susceptibility to invasion, since nearcomplete exploitation can each occur in both species-rich and species-poor communities. Though Lonsdale found a positive association between species richness and invasion, this may arise from the tendency of diverse plant communities to be nutrient poor and therefore more responsive to the effects of human-caused influxes of nutrients.
According to the author, the theory based on fluctuating resource availability might resolve “apparently conflicting and ambiguous results” because
选项 A、it explains how a particular circumstance can produce disparate effects
B、it does not assume that all of the results are instances of the phenomenon that the theory is intended to explain
C、it predicts that seemingly minor variations in research methodology can have a dramatic effect on results
D、its account is based on a statistical tendency rather than on the supposition that the results arise from a causal connection
E、it indicates why a similar outcome may be produced by very different circumstances on different occasions
答案E
解析 根据第二段第一句，作者的理论之所以能够统一不同的理论，就是因为导致生物入侵的资源释放机理太多了，对应选项E。a similar outcome对应生物入侵，very different circumstances指不同的资源释放机理，different occasions指的是生物多和生物少的不同情况。A项正好和选项E相反。B项根据第一段第二句，作者的理论确实只能解决大多数相互矛盾的假说，因此对应选项B的说法，作者的理论不能解释所有的现象。但是这道题问的是为什么作者的理论可以解释相互矛盾的结果，但是选项B的侧重点是作者的理论不能解释的部分，不符合题意。选项B虽然原文提到，但是不符合题意。C项文中未体及minor variations in research methodology。D项文中未提及a statistical tendency。
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