The ancient Nubians inhabited an area in which typhus occurs

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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.

What's the best approach to determine the answer?

OA B

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by GMATGuruNY » Sat Mar 03, 2018 4:31 am
lheiannie07 wrote: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.
Premise: Tetracycline can flourish on the dried grain used for making beer and bread.
Conclusion: Tetracycline explains the low incidence of typhus among ancient Nubians.

Apply the NEGATION TEST.
When the correct answer is negated, the conclusion will be invalidated.

B, negated:
Tetracycline is rendered ineffective as an antibiotic by exposure to the processes involved in making bread and beer.
Here, bread-baking and beer-making render tetracycline ineffective, invalidating the conclusion that tetracycline in the Nubian's bread and beer was responsible for the low incidence of typhus.
Since the negation of B invalidates the conclusion, B is an ASSUMPTION: a statement that MUST BE TRUE for the conclusion to hold.

The correct answer is B.
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