- Wed Jul 03, 2019 1:42 pm
#66050
Complete Question Explanation
Must Be True, Fill in the Blank, CE.
The correct answer choice is A.
The stimulus describes a scenario in which a common enzyme, CYP2A6, has the effect of eliminating nicotine from the body. A correlation is stated: smokers whose bodies make the most common form of CYP2A6 tend to smoke more than those smokers whose bodies make a different form of CYP2A6. The stimulus then asks "why," indicating that the argument will provide a causal explanation for the correlation. The final sentence provides part of a cause/effect conclusion to explain this correlation. The question asks us to fill in the blank with the remainder of the explanation. In other words, we’re looking for an answer choice that provides the most effective causal linkage between the “most common form of CYP2A6” and “smoking more.”
The final sentence of the stimulus points the way by stating that faster nicotine removal leads to quicker cravings for another cigarette (hence, more smoking). But that fact by itself does nothing to connect to those smokers who smoke more, i.e. the ones whose bodies make the most common form of CYP2A6. We therefore need to tie the most common form of CYP2A6 to speed of nicotine removal. Our prephrase should be “the most common form of CYP2A6 removes nicotine faster than any other form of CYP2A6.” If we add that additional causal link to the explanation, we have a perfect causal chain to explain the correlation: Smokers with the most common form of CYP2A6 have faster nicotine removal than smokers with other forms of CYP2A6, causing them to crave additional cigarettes more quickly than those smokers, in turn causing them to smoke more than those smokers.
Answer choice A: This is the correct answer. The answer perfectly fits the prephrase, connecting the most common form of CYP2A6 (the one found in smokers who smoke more) to the notion of faster nicotine removal, calling it the form that “most rapidly eliminates nicotine from the body.”
Answer Choice B: This answer does nothing to explain the correlation, because it does not provide a link between the forms of CYP2A6 and their speed of nicotine removal.
Answer Choice C: This answer would explain a difference in smoking levels between smokers whose bodies make CYP2A6 and those smokers whose bodies do not make CYP2A6 at all. But the question asks us to explain the difference between smokers whose bodies make the most common form of CYP2A6 and smokers whose bodies make some other form of CYP2A6. Thus answer choice C is a shell game, and it cannot provide the specific requested explanation.
Answer Choice D: This is a tempting wrong answer. The problem with answer choice D is that we do not know if (or whether) smokers whose bodies make the most common form of CYP2A6 also make greater quantities of CYP2A6. In fact, the quantity of CYP2A6 made by smokers’ bodies is not addressed at all in the stimulus, so this answer cannot help explain the asserted facts.
Answer Choice E: Answer choice E refers to potential other functions that CYP2A6 serves, but it does nothing to explain the connection between CYP2A6 and nicotine removal (or smoking more).
Must Be True, Fill in the Blank, CE.
The correct answer choice is A.
The stimulus describes a scenario in which a common enzyme, CYP2A6, has the effect of eliminating nicotine from the body. A correlation is stated: smokers whose bodies make the most common form of CYP2A6 tend to smoke more than those smokers whose bodies make a different form of CYP2A6. The stimulus then asks "why," indicating that the argument will provide a causal explanation for the correlation. The final sentence provides part of a cause/effect conclusion to explain this correlation. The question asks us to fill in the blank with the remainder of the explanation. In other words, we’re looking for an answer choice that provides the most effective causal linkage between the “most common form of CYP2A6” and “smoking more.”
The final sentence of the stimulus points the way by stating that faster nicotine removal leads to quicker cravings for another cigarette (hence, more smoking). But that fact by itself does nothing to connect to those smokers who smoke more, i.e. the ones whose bodies make the most common form of CYP2A6. We therefore need to tie the most common form of CYP2A6 to speed of nicotine removal. Our prephrase should be “the most common form of CYP2A6 removes nicotine faster than any other form of CYP2A6.” If we add that additional causal link to the explanation, we have a perfect causal chain to explain the correlation: Smokers with the most common form of CYP2A6 have faster nicotine removal than smokers with other forms of CYP2A6, causing them to crave additional cigarettes more quickly than those smokers, in turn causing them to smoke more than those smokers.
Answer choice A: This is the correct answer. The answer perfectly fits the prephrase, connecting the most common form of CYP2A6 (the one found in smokers who smoke more) to the notion of faster nicotine removal, calling it the form that “most rapidly eliminates nicotine from the body.”
Answer Choice B: This answer does nothing to explain the correlation, because it does not provide a link between the forms of CYP2A6 and their speed of nicotine removal.
Answer Choice C: This answer would explain a difference in smoking levels between smokers whose bodies make CYP2A6 and those smokers whose bodies do not make CYP2A6 at all. But the question asks us to explain the difference between smokers whose bodies make the most common form of CYP2A6 and smokers whose bodies make some other form of CYP2A6. Thus answer choice C is a shell game, and it cannot provide the specific requested explanation.
Answer Choice D: This is a tempting wrong answer. The problem with answer choice D is that we do not know if (or whether) smokers whose bodies make the most common form of CYP2A6 also make greater quantities of CYP2A6. In fact, the quantity of CYP2A6 made by smokers’ bodies is not addressed at all in the stimulus, so this answer cannot help explain the asserted facts.
Answer Choice E: Answer choice E refers to potential other functions that CYP2A6 serves, but it does nothing to explain the connection between CYP2A6 and nicotine removal (or smoking more).