Bunuel
In the ruins of the city-state of Assur, in Ancient Assyria, archaeologists found dried goatskin dating back 3800 years. Analysis of the goatskins showed that they had an unusual pH level that was no lower than that of the calcium carbonate mixture produced by grinding cowrie shells, the most common seashells found on the shore of the Tigris river that runs through Assur. Some believe that this is evidence the Assyrians engaged in the practice of "liming" animal skins: soaking them in alkaline solutions made from crushed seashells in order to create parchment that could be traded with nearby civilizations.
Which of the following, if true, would, together with the information above, provide the best evidence for the claim that the dried goatskins are evidence that the Assyrians engaged in the practice of "liming" animal skins?
A. The calcium carbonate from the cowrie shell is the most common chemical used in modern-day "liming" of parchment and leather.
B. Apart from the Assur discovery, there is reliable evidence that some ancient civilizations, such as the Babylonians, practiced "liming."
C. The goatskins were found in huts that contained equipment known to have been used by Assyrian tradesmen and chemists.
D. Calcium carbonate mixtures of different concentrations can produce a wide range of pH levels in alkaline solutions.
E. Archaeologists matched the goatskins to goat skeletons found on the outskirts of Assur on the banks of the Tigris River.
Knewton Official Explanation
We are told that an archaeological find revealed that goatskins had a pH level that matched (was no lower than) that of a local calcium carbonate mixture. We are asked to find evidence to bolster the claim that the goatskins had an unusual pH level because they had been
"limed" by the Assyrians, indicating that Assyrians engaged in the practice of liming. The correct answer will help clarify that the goatskins were actively "limed" by the Assyrians and reduce the chance that the goatskins had an unusual pH level for any other reason (such as being soaked accidentally in river water with crushed seashells).
Choice C is correct. Choice C states that the goatskins were found in huts used by Assyrian chemists and tradesmen. While this answer choice does not prove that Assyrians were purposefully making their goatskins more basic by
"liming," it does provide concrete physical evidence that the right types of Assyrians were in the right place to accomplish such a task. The tradesmen might have traded the parchment created by the liming (as the argument indicates) and the chemists would have known how to manipulate pH levels.
Choice A states that the chemicals from the cowrie shell are the most common used in modern-day
"liming." Modern-day liming is irrelevant to the liming that may have occurred 3800 years ago. Furthermore, the argument already states that the cowrie shell chemicals may be used for this purpose, so knowing their relative popularity, especially in the modern day, does not help this argument.
Choice B states that other civilizations used
"liming." This does not provide direct evidence that the Assyrians used liming; similar situations do not imply similar results.
Choice D states that calcium carbonate can produce a wide variety of pH levels. However, the prompt claims that the specific calcium carbonate mixture created by cowrie shells could have been that used on the goatskins. Additional knowledge about different calcium carbonate mixtures is irrelevant.
Choice E states that the goatskins matched goat skeletons by the Tigris River. This odd answer choice does not actually provide evidence that Assyrians engaged in
"liming." If the goats had died, or been skinned, by the Tigris, then it is just as possible that the skins got their unusual pH level naturally, through contact with cowrie shells, as it is that they received that level through Assyrian
"liming." Because we already know that the goatskins were found in Assur, this choice offers no new evidence that Assyrians had any hand in giving the goatskins a higher pH level.
Answer: C