GWD1-Q9

zhongyaya

GWD-1-Q9:

The primary purpose of the passage is to

• A     argue against a conventional explanation for the extinction of certain salmon populations and suggest an alternative
  
• B     correct a common misunderstanding about the behavior of salmon in response to environmental degradation caused by human activity
  
• C     compare the effects of human activity on salmon populations with the effects of natural disturbances on salmon populations
  
• D      differentiate the particular effects of various human activities on salmon habitats
  
• E     describe how environmental degradation can cause changes in salmon populations that extend beyond a numerical reduction
  

The numerical effect is
obvious:there are fewer salmon
in degraded regions than in pristine ones; however, habitat loss
also has the potential to reduce
genetic
diversity.Indeed, mostanalysts believe that some kindof environmental degradation underlies the demise of many extinct salmon populations.

注意extend beyond和主题句中的however, reduce genetic diversity


文章里明明说到人类的作用的，为什么正确答案选项里没有。。。另外，我觉得是C，能不能帮忙分析一下为什么错？

victoria820

我个人是觉得这里的environmental degradation其实主要来源于human activity&environment disturbance(如volcanic
eruption)，这样的话就有概括到human activity了。