Healthy lungs produce a natural antibiotic that protects them frominfection by routinely killing harmful bacteria on airway surfaces. People with cystic fibrosis, however, areunable to fight off such bacteria, even though their lungs produce normalamounts of the antibiotic. Since thefluid on airway surfaces in the lungs of people with cystic fibrosis has an abnormallyhigh salt concentration, scientists hypothesize that in high-salt environmentsthe antibiotic becomes ineffective at killing harmful bacteria. Which of the following,if it were obtained as an experimental result, would most decisively underminethe scientists’ hypothesis?
Healthy lungs in which the saltconcentration of the airway-surface fluid has been substantially increased areable to reestablish their normal salt concentration within a relatively shortperiod of time. The antibiotic produced by thelungs is effective at killing harmful bacteria even when salt concentrationsare below levels typical of healthy lungs. The salt concentration of theairway-surface fluid in the lungs of people who suffer from cystic fibrosistends to return to its former high levels after having been reduced to levelstypical of healthy lungs. The lungs of people who suffer from cystic fibrosis are unable tofight off harmful bacteria even when the salt concentration is reduced tolevels typical of healthy lungs. The saltconcentration in the airway-surface fluid of people whose lungs producelower-than-average amounts of the antibiotic is generally much lower than thattypical of healthy lungs.
D是正确答案我可以理解，但是E说产生抗体比平均水平少的人的盐浓度比健康的人低很多，感觉好像也可以weaken，有高手能帮忙解释一下E的问题出在哪吗？
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发表于 2016-9-23 21:56:44
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