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- Sun Jan 20, 2013 12:00 am
#73658
Complete Question Explanation
Assumption. The correct answer choice is (E).
The author tells us that the mercury levels in the feathers of some very old stuffed birds is half the level found in feathers from birds living today. Because the mercury comes from eating fish, the author concludes that the current mercury level in fish must be about double now what it was back when those stuffed birds were alive and eating fish.
For an Assumption question, one approach is to consider a possible objection to the argument. If you can see a problem, the author must have assumed that whatever you saw was not actually a problem. We call that a Defender, and it is the right approach to take with this question.
What is the potential problem? Perhaps in the over 100 years since the birds died and were stuffed, some of the mercury in their feathers leaked out or otherwise diminished? That would be a real blow to this argument, which depends on those mercury levels in the feathers being a good indication of the mercury levels that the birds had ingested through the fish they ate while still living. So, the author must have assumed that no such diminishing must have occurred. That assumption, if correct, would defend against that particular attack on the argument.
Answer choice (A): This answer, if true, would actually undermine the argument, giving us a different reason for the lower level of mercury on the feathers of the stuffed birds. If their diet involved a lower proportion of fish than the diet of today's birds, then the fish they ate could have had just as much mercury as fish have today. The lower level of mercury would be cause not by less mercury, but by eating less fish, perhaps.
Answer choice (B): No assumptions about pollution, of any other possible source of the mercury found in fish either today or in the 1880s, is required by this argument. It doesn't matter where the mercury is coming from. The only thing that matters is the relative amount of mercury found in fish today.
Answer choice (C): Another irrelevant answer. It does not matter whether the mercury is good or bad, important or irrelevant to the fish. The only thing that matters is how much there was in fish in the 1880s compared to how much there is today.
Answer choice (D): Like answer A, this might actually hurt the argument. If the stuffed birds were immature, then perhaps their feathers had not yet had time to accumulate as much mercury as they eventually would have. If anything, the author must have assumed that the stuffed birds had eaten about as much fish as had the living birds that were tested.
Answer choice (E): This is the correct answer choice. This answer defends the argument against a possible attack, an alternate cause for the lower level of mercury in the feathers from the stuffed birds. Negating this answer would destroy the argument, because the lower level of mercury could then be attributed not to less mercury in the fish they ate, but to the stuffing process.
Assumption. The correct answer choice is (E).
The author tells us that the mercury levels in the feathers of some very old stuffed birds is half the level found in feathers from birds living today. Because the mercury comes from eating fish, the author concludes that the current mercury level in fish must be about double now what it was back when those stuffed birds were alive and eating fish.
For an Assumption question, one approach is to consider a possible objection to the argument. If you can see a problem, the author must have assumed that whatever you saw was not actually a problem. We call that a Defender, and it is the right approach to take with this question.
What is the potential problem? Perhaps in the over 100 years since the birds died and were stuffed, some of the mercury in their feathers leaked out or otherwise diminished? That would be a real blow to this argument, which depends on those mercury levels in the feathers being a good indication of the mercury levels that the birds had ingested through the fish they ate while still living. So, the author must have assumed that no such diminishing must have occurred. That assumption, if correct, would defend against that particular attack on the argument.
Answer choice (A): This answer, if true, would actually undermine the argument, giving us a different reason for the lower level of mercury on the feathers of the stuffed birds. If their diet involved a lower proportion of fish than the diet of today's birds, then the fish they ate could have had just as much mercury as fish have today. The lower level of mercury would be cause not by less mercury, but by eating less fish, perhaps.
Answer choice (B): No assumptions about pollution, of any other possible source of the mercury found in fish either today or in the 1880s, is required by this argument. It doesn't matter where the mercury is coming from. The only thing that matters is the relative amount of mercury found in fish today.
Answer choice (C): Another irrelevant answer. It does not matter whether the mercury is good or bad, important or irrelevant to the fish. The only thing that matters is how much there was in fish in the 1880s compared to how much there is today.
Answer choice (D): Like answer A, this might actually hurt the argument. If the stuffed birds were immature, then perhaps their feathers had not yet had time to accumulate as much mercury as they eventually would have. If anything, the author must have assumed that the stuffed birds had eaten about as much fish as had the living birds that were tested.
Answer choice (E): This is the correct answer choice. This answer defends the argument against a possible attack, an alternate cause for the lower level of mercury in the feathers from the stuffed birds. Negating this answer would destroy the argument, because the lower level of mercury could then be attributed not to less mercury in the fish they ate, but to the stuffing process.
