2. 外语
  3. Our terrestrial food supply comes from ecosystems transformed to produce a few comestible species through the removal of competi

Our terrestrial food supply comes from ecosystems transformed to produce a few comestible species through the removal of competi

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问题     Our terrestrial food supply comes from ecosystems transformed to produce a few comestible species through the removal of competitors, predators, and pests, but marine capture fisheries depend on the overall productivity of natural ecosystems. There is, however, increasing concern about the impact of fishing and other human activities on marine ecosystems, which are now far from pristine. One option for moving toward both biodiversity and terrestrial food supply goals is to produce greater yields from less land, thereby freeing land for conservation purposes. By contrast, the objective of maintaining or resorting the biodiversity of marine ecosystems may conflict with the objective of maintaining or increasing our food supply from the sea, since the level of fishing required to achieve the latter may compromise the former.
The primary purpose of the passage is to
选项 A、examine the impact of certain research findings regarding changes to ecosystem biodiversity.
B、discuss a possible implication of a difference between terrestrial and marine food supply sources.
C、describe the consequences of a certain kind of interaction between terrestrial and marine ecosystems.
D、identify an area of ecosystem research in which here are significant uncertainties
E、present evidence that undermines one side of a debate about biodiversity and supports the other.
答案B
解析 本题属于主旨题。本文的主旨便是通过将陆地生态系统和海洋生态系统进行对比，进而得到结论：海洋食物资源和生物多样性很难统一，因此选项B正确。A项文中未提及changes to ecosystem biodiversity。C项本文将海洋和陆地分别讨论，没有讨论两者之间的相互作用。D项从文中看不出significant uncertainties。E项文中没有辩论关于生物多样性。
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本试题收录于： GRE VERBAL题库GRE分类
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