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- Fri Jan 21, 2011 12:00 am
#22915
Complete Question Explanation
Justify the Conclusion-CE. The correct answer choice is (D)
The conclusion is that destructive geophysical process is the causal factor in the density of meteorite craters in an area relative to other areas. In other words, the conclusion is that events such as earthquakes, volcano eruptions, and so on, explain why there are more meteorite craters in some places than in others. As evidence, the argument points out that there are more meteorite craters found in geologically stable areas.
The stimulus contains causal reasoning, so you should remember that ways of weakening or strengthening a causal argument. Also, the clearest objection to the argument is that an equally likely cause of crater distribution is that meteorites simply struck some regions of Earth more frequently than others.
Answer choice (A): This answer choice suggests that coincidence could play a role. If this choice is assumed, some areas could have been struck as often as others, but start off appearing different because of how close the meteorite strikes were to each other. At that point, geophysical processes might not be the cause of the regions appearing different from each other, so this choice weakens the argument by suggesting another cause, and is incorrect.
Answer choice (B): This choice removes the cause from the effect. If the current stability of a region does not establish its past stability, over time two regions that appear different could have had the same average stability, and so stability would not be a very good explanation for the existence of any but the most recent craters. This choice weakens the argument, and is wrong.
Answer choice (C): It is true that if lately the earth has been struck more often, the current geological conditions might be more important than extremely past conditions, and the argument would be improved. However, it is still possible that there were enough strikes in geologically distant, dissimilar times to create the difference. For instance, perhaps "geologically recent" covers a relatively small proportion of earth's existence. This choice does not justify the argument, and certainly does not deal with the most important objection, so this choice is wrong. As a note, this choice seems to eliminate the possibility raised by answer choice (B), and you can be certain that was the reason the LSAT writers put this choice immediately afterwards. If you have a good prephrase, you are less likely to be drawn in by this kind of trick. As mentioned, answer choice (C) only superficially seems to eliminate the concern raised in answer choice (B), and does not address the main objection.
Answer choice (D): This is the correct answer choice. It establishes that one region has been, on average, struck no more than any other region, and that the distribution of strikes has been even. That means the initial distribution of meteorite strikes is not a cause for the density of craters in a region, and in commonsense terms the only remaining plausible causes involve geophysical processes. Even though the stimulus seemed to concern processes related to stability rather than those of erosion, at least this answer choice does not weaken the conclusion. Furthermore, since answer choice (C) fails to eliminate initial distribution as a cause, answer choice (D) is simply a better choice to justify a causal argument. Remember, not all LSAT answers will be perfect, but you can still be certain that this choice is correct, because it is the only answer that correctly deals with the causal reasoning in the stimulus.
Answer choice (E): This answer choice weakens the argument by suggesting that perhaps the craters in geologically unstable regions are simply undiscovered.
Justify the Conclusion-CE. The correct answer choice is (D)
The conclusion is that destructive geophysical process is the causal factor in the density of meteorite craters in an area relative to other areas. In other words, the conclusion is that events such as earthquakes, volcano eruptions, and so on, explain why there are more meteorite craters in some places than in others. As evidence, the argument points out that there are more meteorite craters found in geologically stable areas.
The stimulus contains causal reasoning, so you should remember that ways of weakening or strengthening a causal argument. Also, the clearest objection to the argument is that an equally likely cause of crater distribution is that meteorites simply struck some regions of Earth more frequently than others.
Answer choice (A): This answer choice suggests that coincidence could play a role. If this choice is assumed, some areas could have been struck as often as others, but start off appearing different because of how close the meteorite strikes were to each other. At that point, geophysical processes might not be the cause of the regions appearing different from each other, so this choice weakens the argument by suggesting another cause, and is incorrect.
Answer choice (B): This choice removes the cause from the effect. If the current stability of a region does not establish its past stability, over time two regions that appear different could have had the same average stability, and so stability would not be a very good explanation for the existence of any but the most recent craters. This choice weakens the argument, and is wrong.
Answer choice (C): It is true that if lately the earth has been struck more often, the current geological conditions might be more important than extremely past conditions, and the argument would be improved. However, it is still possible that there were enough strikes in geologically distant, dissimilar times to create the difference. For instance, perhaps "geologically recent" covers a relatively small proportion of earth's existence. This choice does not justify the argument, and certainly does not deal with the most important objection, so this choice is wrong. As a note, this choice seems to eliminate the possibility raised by answer choice (B), and you can be certain that was the reason the LSAT writers put this choice immediately afterwards. If you have a good prephrase, you are less likely to be drawn in by this kind of trick. As mentioned, answer choice (C) only superficially seems to eliminate the concern raised in answer choice (B), and does not address the main objection.
Answer choice (D): This is the correct answer choice. It establishes that one region has been, on average, struck no more than any other region, and that the distribution of strikes has been even. That means the initial distribution of meteorite strikes is not a cause for the density of craters in a region, and in commonsense terms the only remaining plausible causes involve geophysical processes. Even though the stimulus seemed to concern processes related to stability rather than those of erosion, at least this answer choice does not weaken the conclusion. Furthermore, since answer choice (C) fails to eliminate initial distribution as a cause, answer choice (D) is simply a better choice to justify a causal argument. Remember, not all LSAT answers will be perfect, but you can still be certain that this choice is correct, because it is the only answer that correctly deals with the causal reasoning in the stimulus.
Answer choice (E): This answer choice weakens the argument by suggesting that perhaps the craters in geologically unstable regions are simply undiscovered.
Effect: greater abundance of craters