LSAT C2 - Section 3 - Question 15

Question Stem
The key words in this question stem are "explain" and "discrepancy." They tell us that we're doing an RRE question.

But perhaps more important is the phrase "most help to" because they reveal the fact that the LSAT writers really mean what they say. Here, they asked for an answer choice that would "most help to explain" as opposed to an answer choice that "definitively explains."

This feels unfair because in the past (on other, easier RRE questions) the writers also ask for answers that "most help to explain" yet we end up with answers that "definitively explains" without recourse to any assumptions. Nonetheless, they mean what they say. The bar for the correct answer is comparative. (A) is correct because it "most helps" i.e., it helps more than (B), (C), (D), or (E) to explain. Yes, (A) does need assumptions. No, (A) does not explain the entire phenomenon. But that doesn't mean (A) is wrong. It just means that (A) is right and needs assumption and doesn't explain the entire phenomenon. Why is it right when in the past answers that need assumptions or don't explain the entire phenomenon have been wrong? Because in those past RRE questions there were better answers. In this RRE question, there are only worse answers.

This "better than the others" correct answer is something that also appears in difficult Weaken and Strengthen questions. You'll also be placed in a position where the correct answer feels like it needs some assumptions to carry the day, but that doesn't mean it's wrong. Look closely at the other answers and you'll see that they require more unreasonable assumptions.

Stimulus
We're told a few facts. The number of deer in North America has increased dramatically since the 60s. That fact seems to be at odds with the fact that hunters today kill just as many or more deer than they did in the 60s. It also seems to be at odds with the fact that natural predators of deer (like wolves) has increased. It also seems to be at odds with the fact that suburbs are encroaching upon deer habitats.

Okay, so this is a perplexing phenomenon in need of an explanation. All three facts cited would cause the deer population to decrease. Yet, in spite of these pressures, the deer population has increased. There must be some other causal force lifting up the deer population.

Answer Choice (A)
Answer choice (A) gives us that causal force but it requires assumptions. (1) it requires an assumption that deer is part of the "most" subset of wildlife. (2), it requires that the adverse affects of those pesticides disappear after a few decades of non-use. (3), if both of these assumptions are granted, then (A) only explains the increase in deer population from the 70s onward. It does not explain the increase from the 60s to the 70s.

How reasonable is assumption (1)? Note that (1) said "most" and not "half" or "a minority." Had it said "all" we wouldn't need an assumption. But "most" is pretty good. If you had to bet, you'd bet with, not against "most." That's the more reasonable bet.

How reasonable is assumption (2)? It's hard to say. Especially if you don't know about pesticides. But the fact of the matter is that most pesticides' adverse effect do not persist more than several years. And so given the time horizon of decades, it's safe to assume that their adverse effects have disappeared. I'm not saying that you should know this. I'm only saying that this is the truth and therefore a more defensible assumption.

Both assumptions and the failure to fully explain the phenomenon are real issues with (A). They are (A)'s weaknesses. If there is an answer (X) such that (X) does not need those assumptions while explaining the phenomenon more fully, then (X) would be a better answer. As it turns out, there is no answer (X).

One more thing to note: it is not an issue with (A) whether these pesticides adversely affected wolves and other deer predators. We don't care because the stimulus already told us that the number of wolves (and other deer predators) increased. So either they didn't affect these predators or they did and the effect was too small. Either way, doesn't matter because their numbers increased. We don't care why they increased.

Answer Choice (B)
Answer choice (B) starts with "recently" so that's already an issue. At best, it explains a smaller part of the phenomenon than (A) since "recently" encompasses a smaller timeframe than the many decades that have passed since the 70s. (B) is worse than (A) on this point. But more importantly, (B) says that "attempts" have been made to protect deer habitat. It's baiting you to assume that those attempts are successful and that if successful, they counteract what you were already told in the stimulus: the "suburbs increasingly encroach on deer habitats." No, no. The fact is that the "suburbs increasingly encroach on deer habitats" in spite of these attempts in (B) to protect the deer habitat. That means either (1) these attempts failed or that (2) these attempts succeeded but were too tiny to make a difference. Either way, it doesn't explain any part of the phenomenon.

Answer Choice (C)
Answer choice (C) is baiting you to misinterpret the claim in the stimulus that "hunters kill no fewer deer today." That statement means that the total number of deer deaths attributable to hunters is either the same or higher today as compared to the 60s. That statement does not tell you how many hunters there were in the 60s compared to today. Frankly, it doesn't matter. All you care about is the number of hunter-related-deer-deaths, not whether there are more or less hunters. (C) baits you into thinking that because there are fewer hunters, that means there must be fewer hunter-related-deer-deaths. Not only is that an unwarranted assumption, there is explicit text in the stimulus implying the contrary. The fact that hunter-related-deer-deaths is the same or higher today coupled with the fact in (C) that there are fewer hunters today logically implies that each hunter today is more deadly than his or her counterpart in the 60s in killing deer. Today's hunters kill more deer per hunter than the hunters in the 60s. That's an inference you'd expect to see in a must be true question.

Answer Choice (D)
Answer choice (D) gives us a partial explanation of why the number of wolves are on the rise. "Much" (it did not say "all") of the increase is due to wolves born in captivity and released into the wild. How does this affect the phenomenon? Well, if you want it to explain the phenomenon, you'd have to make an unlikely assumption. The big assumption is that wolves born in captivity are poor hunters. Sure, it's possible. But it's less likely than the alternative (that they are decent hunters) because presumably the point of this conservation (of wolves) effort is to reintroduce wolves that wouldn't just die of starvation once they're released. Why go through the hassle of birthing wolves in captivity if they cannot survive in the wild? Be careful about arguing in "possibilities." Rather think in realistic "probabilities" and what is more likely. It's just more likely that these captive-born-wolves once released are effective hunters than ineffective hunters.

Now, let me concede the point above, meaning, let's pretend that these captive-born-wolves once released are ineffective hunters. Okay, but then, we know that wolves are just a subset of the deer predators. The rest of that set also increased. There are more non-wolves predators of deer which still exert a downward pressure on the deer population.

Answer Choice (E)
Answer choice (E) doesn't explain the phenomenon. Rather it tries to predict what will happen in the future as a consequence of the phenomenon. It says that the chances of deer becoming afflicted with famine and disease is increased.