SET 16 - III - 18[求助]

jubel

In experiments in which certain kinds of bacteria were placed in a generous supply of nutrients, the populations of bacteria grew rapidly, and genetic mutations occurred at random in the populations. These experiments show that all genetic mutation is random.

Which one of the following, if true, enables the conclusion to be properly drawn?

(A) Either all genetic mutations are random or none are random.

(B) The bacteria tested in the experiments were of extremely common forms.

(C) If all genetic mutations in bacteria are random, then all genetic mutations in every other life form arc random also.

(D) The kind of environment in which genetic mutation takes place has no effect on the way genetic mutation occurs.

(E) The nutrients used were the same as those that nourish the bacteria in nature.
选A，为什么不选C啊？

谢谢。

jubel

没人理

cranberry

c is not the answer because in the passage only certain kinds of bacteria are tested and the conclusion is based on all the mutations and there is a gap ,and c only says that if bacterias ...then all,but it fais to close the gap between some kinds of bacteria and all kinds of bacteria.

pocahontas

yup. and when i saw this Q,i mistook "all genetic mutation" in the lsat sentence as [all life form's genetic mutation]. Instead all here means all kinds of bacteria, as a counterpart of "certain kinds of bacteria " in the first sentence.