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705-805 Level|   Assumption|      
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Raman109
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The ancient Nubians inhabited an area in which typhus occurred, yet su 11 Sep 2023, 04:37
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Option A "The tetracycline deposits did not form after the bodies were buried." is a weakner and not an assumption whose negation will destroy the conclusion. Let's see how
Negation - The tetracycline deposits did form after the bodies were buried. But it's also possible that some of that tetracycline came to bones by the process defined by the author in the argument through diet.

Option D, "Tetracycline is not rendered ineffective as an antibiotic by exposure to the process involved in making bread and beer." is an assumption because its negation will destroy the conclusion. Let's see
Negation - Tetracycline is rendered ineffective as an antibiotic by exposure to the process involved in making bread and beer. The conclusion that "tetracycline in their food probably explains the low incidence of typhus among ancient Nubians." is shattered.
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The ancient Nubians inhabited an area in which typhus occurred, yet su 04 May 2024, 14:35
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amishag
answer explanations like the ones in the comments tell me that it is very easy to defend an answer choice when you know that it is the correct answer choice. some answer explanations on CR forum seem extremely biased toward the correct answer choice because the authors are especially trying to prove that it is correct. it would be interesting to read someone's thoughts while they are answering the question and before they have seen the answer.
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­Perfectly summed up chiranjeevsingh's answer. His answer is absolutely wrong but just because the official answer is now known to him, he is defending it
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The ancient Nubians inhabited an area in which typhus occurred, yet su 18 Jul 2024, 05:31
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ChiranjeevSingh

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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.



 
Let me explain why option A is wrong.

First of all, the following version of A would be correct:

The tetracycline deposits did not form from the tetracycline that entered into the bodies after the bodies were buried.

This version is correct because the negation of this option would mean that the tetracycline deposits we see today are the result of the tetracycline that entered into Nubians' bodies after they were buried. So, this tetracycline could not have prevented typhus while they were living since it entered after their bodies were buried.

However, the original option A is wrong because the negation of the original option A means that the tetracycline deposits formed after the bodies were buried. We don't have a problem with this; the deposits could have formed after the death of those people; we just need tetracycline to be in their bodies while they were alive. Rather, "deposits" are expected to form over a long period of time. Thus, the fact that they formed after the death of Nubians doesn't mean that tetracycline was not there in the bodies of Nubians while they were alive. Tetracycline could easily have been in their bodies while they were alive, and then once they died, deposits formed over a long period of time. Simple! :)
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­Brilliant! ChiranjeevSingh

But in option-D, even if tetracycline is rendered ineffective by the process in preparing the food items, as long as the bacteria flourishing in those grains (and so in the food) survives the cooking process, can it not simply produce tetracycline again? In this case D would not be necessary. 
 ­GMATNinja , KarishmaB . Could you also comment on this please? Thanks
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The ancient Nubians inhabited an area in which typhus occurred, yet su 05 Aug 2024, 10:58
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PReciSioN
Brilliant! ChiranjeevSingh

But in option-D, even if tetracycline is rendered ineffective by the process in preparing the food items, as long as the bacteria flourishing in those grains (and so in the food) survives the cooking process, can it not simply produce tetracycline again? In this case D would not be necessary.

­GMATNinja , KarishmaB . Could you also comment on this please? Thanks
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­That's a stretch because the passage tells us that the bacterium can flourish on the DRIED grain used for making beer and bread. In order for your scenario to work, we have to assume that the bacterium can flourish not only (1) on the dried grain­ used for beer and bread but also (2) in the beer and bread itself.

In other words, you're introducing a new argument: that tetracycline can form in finished beer and bread. Even if that were true, it is NOT the same argument made by the author -- the author's argument is that the tetracycline forms on the dried grains that are used as ingredients for the beer and bread.

Choice (D) might not be required for your new argument, but it IS required for the author's argument.

I hope that helps!
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The ancient Nubians inhabited an area in which typhus occurred, yet su 08 May 2025, 08:06
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I was also confused between A and D, but as the right approach, I went to the conclusion and the conclusion is "Thus, tetracycline in their food probably explains the low incidence of typhus among ancient Nubians."

So author says this antibiotic is responsible for low incidence and D when negated directly attacks the argument on those lines

Negated D: Tetracycline is rendered ineffective as an antibiotic by exposure to the process involved in making bread and beer. - hence it cannot be the reason for low incidence and thus the argument is weakened when negated. This has to be the assumption. So D
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The ancient Nubians inhabited an area in which typhus occurred, yet su 14 Oct 2025, 02:57
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Let's break down the argument:

The author presents a puzzle: Ancient Nubians lived where typhus was common, but their skeletons rarely show typhus evidence. Here's the explanation offered:

  1. Nubian skeletons contain tetracycline (an antibiotic)
  2. This tetracycline came from bacteria that grew on grain
  3. Nubians used this grain to make bread and beer (dietary staples)
  4. Conclusion: The tetracycline in their food explains the low typhus rates

Now here's the key question you need to ask: What gap exists between the premises and conclusion?

Notice the logical jump happening here. The argument moves from "tetracycline was present in the grain" directly to "tetracycline in their food protected them from typhus." But think about what happens between these two points—the grain goes through a transformation process. It gets baked into bread and fermented into beer.

Here's the critical insight: For this argument to work, the food preparation process can't destroy the tetracycline's antibiotic properties.

Think about it this way: If baking bread or brewing beer destroyed the tetracycline's effectiveness, then consuming these foods wouldn't have provided any disease protection whatsoever. The entire causal chain collapses.

This is exactly what (D) addresses: "Tetracycline is not rendered ineffective as an antibiotic by exposure to the process involved in making bread and beer." This assumption bridges the gap between "tetracycline in grain" and "tetracycline protecting Nubians."

Why the other answers don't work:

  • (A) Post-burial formation - This addresses when the deposits formed, but not whether the tetracycline was effective during the Nubians' lives.
  • (B) Effects on other diseases - The argument is specifically about explaining low typhus rates. What happens with other diseases is outside the scope.
  • (C) Typhus being fatal - The severity of the disease doesn't affect whether tetracycline could prevent or treat it.
  • (E) Bread/beer being the only sources - This is too extreme. The argument only needs these foods to contain enough tetracycline to be protective, not that they're the exclusive sources.

For the complete framework on how to systematically identify assumptions using the negation test technique, plus the underlying patterns that apply across all assumption questions, you can check out the step-by-step solution on Neuron by e-GMAT. You'll also discover detailed explanations with practice quizzes for many other official CR questions here on Neuron, including analytics that track your performance across different question types.

Hope this helps clarify the reasoning! Let me know if you have any questions.
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The ancient Nubians inhabited an area in which typhus occurred, yet su 16 Oct 2025, 23:56
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IMO , we can eliminate Option A, through negation and Select D.

The correct answer choice in an Assumption question is essentially a part of the stimulus.

The Conclusion: tetracycline in their food probably explains the low incidence of typhus among ancient Nubians.
This conclusion would hold if the tetracycline is not damaged by the process of making beer or bread. This is what option D says.

If you negate option A, it would mean that the tetracycline deposits happened after the bodies were buried. This does nothing to break the conclusion of the author.
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