tpo17阅读一道题请求大神指导

celtspiritUID: 3004720

At times, it is actually possible to watch the effects of natural selection in host-parasite relationships. For example, Australia during the 1940 s was overrun by hundreds of millions of European rabbits. ■The rabbits destroyed huge expanses of Australia and threatened the sheep and cattle industries. In ■1950, myxoma virus, a parasite that affects rabbits, was deliberately introduced into Australia to control the rabbit population. ■Spread rapidly by mosquitoes, the virus devastated the rabbit population. ■The virus was less deadly to the offspring of surviving rabbits, however, and it caused less and less harm over the years. Apparently, genotypes (the genetic make-up of an organism) in the rabbit population were selected that were better able to resist the parasite. Meanwhile, the deadliest strains of the virus perished with their hosts as natural selection favored strains that could infect hosts but not kill them. Thus, natural selection stabilized this host-parasite relationship.

5. Which of the following can be concluded from the discussion in paragraph 3 about the Australian rabbit population?
A. Human intervention may alter the host, the parasite, and the relationship between them
B. The risks of introducing outside organisms into a biological community are not worth the benefits.
C. Humans should not interfere in host-parasite relationships.
D. Organisms that survive a parasitic attack do so in spite of the natural selection process.
答案选A。人类只是引入了另一物种，但是最后作用的是natural selection，并不是人类啊？

秋雨荆州UID: 2903781

其他三项都不太正确，可以排除掉，选项A是不是可以这么理解：人类为了控制兔子的数量，引入了virus，从而产生了新的host-parasite关系。

longlongblackUID: 3263103

同问！！！我也觉得奇怪，觉得这里面人类就是个打酱油的，只是用于介绍病毒是怎么引进的而已。反正是很难理解。

Ian.HuUID: 3369065

今天刚做到这里，我觉得题干中有conclude啊，conclude难道不是对段落的大意进行总结么？怎么也不会选A，不过答案就是。

七虫1七花UID: 2959561

又沒人保證什麽一定正確咯   一兩道沒大不了   ETS真題的答案誰都沒

cinkieUID: 2933620

人类引入virus就是要利用natural selection来消灭那些对virus抗性比较弱的兔子，因此留下来的都是对这种virus抗性比较强的兔子，因此来控制兔子数量。这样来说吧，natural selection只是人类消灭兔子的一个tool，主导作用还是人类搞出来的virus

也可以用排除法，BC明显错，D有点绕，但后面看到in spite of natural selection process就知道D错了，剩下来的兔子也是由自然选择选出来的

小菜牛UID: 3329566

楼上说的很清楚

celtspiritUID: 3004720

cinkie 发表于 2012-9-9 22:41
人类引入virus就是要利用natural selection来消灭那些对virus抗性比较弱的兔子，因此留下来的都是对这种vir ...

感谢解答，有点绕

黑斯廷斯UID: 3656927

其实我觉得这题真的不必太纠结。
4个选项全错，真正考试的时候，不会有这种题的，不用担心。
人不要看到自己的答案和官方的答案不同就拼命给官方答案找理由，不要给自己太大压力，顺便说下，我自己做TPO17就只错了这一题，恨死官方答案！

wenliping1209UID: 3194502

我做的时候就直接用排除法了~因为BCD都不对，A虽然不太符合conclude，但是并没有违背原文的意思，所以是最佳选项。