LSAT 5 - Section 1 - Question 12

This is a sufficient assumption question: this question stem includes “properly drawn if which one of the following is assumed?”

Sufficient assumption questions tend to be very formal. We’re looking for a rule that would 100% validate the conclusion, specifically by bridging the premise and conclusion through the rule. Not only are we extrapolating the rule from our argument, but we’re also using that rule to render the argument “valid.” The way to prephrase our answer choice is by tying our premises and conclusion together into a rule: “If [premise] → then [conclusion].” Sometimes, rules are a little too chunky and don’t capture the gap accurately. This question is a great example of why.

The first sentence introduces a phenomenon: impact craters have been found everywhere, but more are found in geologically stable regions. Basically, in the most stable regions, for example in Canada, we find a lot more impact craters than we do in Japan. This does make sense. Being geologically stable has nothing to do with the frequency and location of meteor impacts; earthquakes, tsunamis, and tectonic movements don’t impact space activity.

Our next sentence is our conclusion, explaining this phenomenon: the level of land destruction is lower in these regions, so presumably, the impact craters would remain intact. This seems completely logical. However, this is one possible explanation. The argument hasn’t done anything to address any other explanation. Either way, we can’t say the explanation for the higher number of these impact craters being visible in these regions must be because they weren’t destroyed by geophysical processes. To bridge this gap, we have to block other explanation with a rule like: “If impact craters are visible in areas that are geologically stable, it must be because they weren’t destroyed.” Remember that our correct answer choice may not mirror our rule; it could also block any other explanation.

Answer Choice (A) This is not correct. If a meteor obliterates a trace of another meteor, how does that help validate that the craters weren’t destroyed in the more stable regions? This does not help validate our conclusion.

Answer Choice (B) The rates fluctuating don’t help support the explanation for why more craters are visible in stable areas. In fact, the rate of geophysical destruction varying within any region might actually hurt our premise.

Answer Choice (C) Just because there are more meteors striking down, that doesn’t support our conclusion for the explanation for visible meteors in stable areas. In fact, this could weaken the argument - what if all of the increased meteor showers hit stable regions?? Then the explanation the conclusion gives would be totally false.

Correct Answer Choice (D) It’s rejecting the overlooked possibility that the other explanation for why there are more craters in stable regions is simply because there were more craters that hit the areas. With this premise inserted in our argument, we can properly draw the conclusion: since craters were hit everywhere evenly and are more visible in stable regions, the explanation must be that these stable areas aren’t prone to destruction and the craters are preserved.

Answer Choice (E) If one area is studied more than others, that does not help support the explanation. This is not an issue of discovery or what craters are not known. We have to accept the premise that more craters show up in stable regions.