请求帮助GWD-18-Q30

dannya

The ancient Nubians inhabited an area in which typhus occurs, yet surprisingly few of their skeletons show the usual evidence of this disease.The skeletons do show deposits of tetracycline, an antibiotic produced by a bacterium common in Nubian soil.This bacterium can flourish on the dried grain used for making two staples of the Nubian diet, beer and bread.Thus, tetracycline in their food probably explains the low incidence of typhus among ancient Nubians.

Which of the following is an assumption on which the argument relies?



A.Infectious diseases other than typhus to which the ancient Nubians were exposed are unaffected by tetracycline.

B.Tetracycline is not rendered ineffective as an antibiotic by exposure to the processes involved in making bread and beer.

C.Typhus cannot be transmitted by ingesting bread or beer contaminated with the infectious agents of this disease.

D.Bread and beer were the only items in the diet of the ancient Nubians which could have contained tetracycline.

E.Typhus is generally fatal.

为什么D不对？有人说是无关选项，为什么？

demonada

古代在N这个地方有伤寒发生，奇怪的是却很少有遗骨显示这种疾病的证据。  遗骨显示了一种普遍存在于N土壤的细菌产生的抗体的沉积。 这种细菌能是做两种主食的谷物生长茂盛。因此，食物中的抗体可以解释伤寒发生概率低的原因。问前提是什么？
哦，顿悟！其实题目是这样的，这种抗体可以抵御伤寒，所以伤寒的发生率低了，而B就是这个假设：加工过程不会导致抗体失效。