joshnsit wrote:
The ancient Nubians inhabited an area in which typhus occurred, 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) The tetracycline deposits did not form after the bodies were buried.
(B) The diseases other than typhus to which the ancient Nubians were exposed would not be affected by tetracycline.
(C) Typhus is generally fatal.
(D) Tetracycline is not rendered ineffective as an antibiotic by exposure to the process involved in making bread and beer.
(E) Bread and beer were the only foods eaten by the ancient Nubians which could have contained tetracycline.
Similar question from GMATPrep:
LINKOne of the reasons I prefer a "missing link" strategy for CR assumption questions, as opposed to the more popular negation technique, is that I get to leave everything alone and simply drop in a line wholesale to test whether I can go from premise to conclusion seamlessly. Try (A) and (D), respectively, in this manner:
PASSAGE (premise):
This bacterium [common in Nubian soil and that produces an antibiotic called tetracycline]
can flourish on the dried grain used for making two staples of the Nubian diet, beer and bread.ANSWER: A. The tetracycline deposits did not form after the bodies were buried.
PASSAGE (conclusion):
Thus, tetracycline in their food probably explains the low incidence of typhus among ancient Nubians.It seems a little strange to discuss the Nubian diet as a premise, then insert information about tetracycline and skeletal remains, for which we have to reach back further in the passage to qualify, and then return to the idea of
food being a primary determinant in
the low incidence of typhus among ancient Nubians. I would not write off the answer, but I cannot say that X (the premise) connects to Z (the conclusion) through it. I would
yellow light the answer in my first pass, but I would be hoping for a better, more fitting bridge to connect the two lines from the passage. Try (D) out in the same way:
PASSAGE (premise):
This bacterium [common in Nubian soil and that produces an antibiotic called tetracycline]
can flourish on the dried grain used for making two staples of the Nubian diet, beer and bread.ANSWER: Tetracycline is not rendered ineffective as an antibiotic by exposure to the process involved in making bread and beer.
PASSAGE (conclusion):
Thus, tetracycline in their food probably explains the low incidence of typhus among ancient Nubians.Wow, if that is not a perfect bridge or "missing link," then I am not sure what more we could want. The premise mentions the
diet of the ancient Nubians, the answer choice rules out the possibility that an active antibiotic compound suspected to be a part of that diet would be
rendered ineffective prior to consumption, and then the conclusion about
food follows. This is a
green light answer, one that we cannot find fault with.
Between (A) and (D), then, the latter is
directly related to the premise and the conclusion that follows, so it is the safer bet, and we should choose it. The order in which the sentences are presented in the passage is crucial to the process I have outlined. Anyway, I hope that helps. Just remember that when you find friction, you are probably not pursuing the path of least resistance, and in Verbal, that often translates into a wrong answer.
Good luck with your studies.
- Andrew
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