gwd-24-15

24-15 Healthy lungs produce a natural antibiotic that protects them from infection by routinely killing harmful bacteria on airway surfaces. People with cystic fibrosis, however, are unable to fight off such bacteria, even though their lungs produce normal amounts of the antibiotic. The fluid on airway surfaces in the lungs of people with cystic fibrosis has an abnormally high salt concentration, scientists hypothesize that in high salt environments the antibiotic becomes ineffective at killing harmful bacteria.

Which of the following, if it were obtained as an experimental result, would most decisively undermine the scientists’ hypothesis?

1. Healthy lungs in which the salt concentration of the airway-surface fluid has been substantially increased are able to reestablish their normal salt concentration within a relatively short period of time.


2. The antibiotic produced by the lungs is effective at killing harmful bacteria even when salt concentrations are below levels typical of health lungs.


3. The salt concentration of the airway-surface fluid in the lungs of people who suffer from cystic fibrosis tends to return to its former high levels after having been reduced to levels typical of healthy lungs.


4. The lungs of people who suffer from cystic fibrosis are unable to fight off harmful bacteria even when the salt concentration is reduced to levels typical of healthy lungs.


5. The salt concentration in the airway-surface fluid of people whose lungs produce lower-than-average amounts of the antibiotic is generally much lower than that typical of healthy lungs.

请教这题我看好像是消弱但是找不出为什么e的原因。谢谢。。

E：The salt concentration in the airway-surface fluid of people whose lungs produce lower-than-average amounts of the antibiotic is generally much lower than that typical of healthy lungs.

集中看看蓝色部分呢？当然还有题干

这题答案是?????e or d

应该选择D吧!!!

题目说病人在 suffer cystic fibrosis 的情况下 high salt environments ,从而得出结论 high salt environments 是 antibiotic 失效的原因.

D说即使在没有这个原因的情况下同样有这个结果,从而就否定了这个原因.

即 undermine 了这个 hypothesis

4楼的gg, 那E 是not related?

(我又错了，郁闷ing！)

是d,那么e是无关选项了。

异因，同果，因此削弱原来推论。