This is a straight forward question stem for an NA question. The argument depends on the assumption in the answer. This is asking for necessity.
First off in this stimulus, that is a powerful sounding book. I don’t know of anything this convincing, so we’ve set a very extreme characteristic to this book. But remember that on the LSAT, we accept the assertions as true. So this book is all powerful in its persuasiveness. Members of the Earth Association gave away 2,000 copies last month. Given its persuasive power, that seems like a worthwhile thing to do for an environmental organization. “Thus” is introducing the conclusion here in the final line: The EA converted 2,000 people to the cause.
Well, a lot of problems might come to mind. First, it’s not enough for someone to own the book to be persuaded by it. It still needs to be read. Did any of these people they gave the books to read it? Also, to be converted, the recipients must not have already been environmentalists. Who are these people? The Earth Association better not have been distributing these at a convention for environmentalists, or I’m skeptical that they haven’t just been handing these out to people who were already environmentalists. Maybe these issues are obvious to some of us, maybe not to others. I do think these are particularly conspicuous compared to the average NA question, but we need not see these as problems. Whether you saw these or not, you still want to keep an open mind with the answer choices. There may very well be something else. With NA, there is almost always other directions a correct answer could take. For example, another NA here would be something like, “Copies of To Save the Earth are not printed in a font too small for any of the 2,000 recipients to read.” Bet no one predicted that, but it would be the right answer if provided. It goes to the same idea that each recipient actually read it, but its presented in a surprising way that may be difficult to recognize if we’re committed to looking for any answer in particular.
Answer Choice (A) Well that doesn’t have to be true. The more the merrier. We might have an issue if other organizations gave it to the same recipients, but this doesn’t say that. If it did, then these people would get this book with or without the Earth Association and so that could be a problem for their claim. If you selected this, did you think that’s what it said? Read carefully!
Answer Choice (B) This is wrong, but it’s a little tricky. Their “willingness” to buy it does not particularly matter. They could both be willing to buy it and not have bought it. I’d be willing to buy lots of things I have not actually bought. So just because they’d’ve been willing to buy it doesn’t mean they’d have obtained (and read) a copy. Furthermore, if they were willing to buy it, it doesn’t at all matter that they would have been willing to have bought it from the Earth Association. Any bookstore or online retailer or yard sale or anything else would be fine. This just doesn’t have to be true.
Answer Choice (C) Recycled paper? No. We might expect this book to be sustainably printed, but this has nothing to do with its persuasive power or whether or not the Earth Association has changed hearts and minds.
Correct Answer Choice (D) Here it is. If someone was already committed to the cause when the Earth Association gave them the book, then the Earth Association cannot claim to have converted that person to the cause they were already committed to.
Answer Choice (E) This is another slippery one. We do need each recipient to convert to the environmentalist cause, but that need not mean they embrace the specific brand of environmentalism advocated for by the Earth Association. That is an additional assumption which we are not at liberty to make and which prevents this answer from being necessary.
We can identify this question as Method of Reasoning because of the question stem: “Which one of the following most accurately characterizes Dr. Santos’ response to the hypothesis advanced by Dr. Libokov?”
When dealing with a Method of Reasoning question, we know we are looking for an answer choice that correctly describes the structure of our entire argument. Our correct answer is going to fit the argument exactly. Our wrong answer choices likely explain argument structures we are familiar with, but that simply don’t apply to the specific question we are looking at. Knowing what the right and wrong answers are going to do, we can jump into the stimulus.
Immediately we should make note of the two speakers at play. This means we could possibly be dealing with two different conclusions with different levels of support. Our first speaker, Dr. Libokov, tells us about the “S” reptile (whose technical name is far too long to recall). The speaker explains that the S reptile has disappeared throughout the rest of the world with the exception of a few islands around New Zealand. Dr. L concludes the explanation for this is simple, on account of the development of mammal species on larger islands that feed on the S reptile’s eggs, leading to extinction.
This first argument doesn’t have any glaring issues. While Dr. L certainly assumes that mammals became enough of a threat to the S reptile that it considerably reduced their numbers, the reasoning behind the speaker’s conclusion lines up. This very well may be why our second speaker, Dr. Santos, provides support to affirm Dr. L’s position. Dr. Santos explains that in addition to what we heard from the first speaker, any islands where mammals have been introduced ultimately see an extinction of the S reptile.
In this way Dr. Santos does fill in the itty bitty gap in Dr. L’s argument. While we can conclude a major predator would have an impact, we don’t quite have the information to assume the mammals would lead to inevitable extinction. But Dr. Santos confirms that actually we can say there is a guarantee if we introduce mammals the S reptile will decline in population. Knowing our correct answer choice will highlight how our second speaker adds to the first, we can proceed into answer choice elimination.
Answer Choice (A) Identifying a flaw means Dr. Santos would be weakening the argument. Knowing our second speaker supports (perhaps more importantly, does not discredit) we can eliminate this answer choice.
Answer Choice (B) If our second speaker were adding nothing to the discussion as claimed by this answer choice, we would expect to see an exact repetition of Dr. L’s argument. We can eliminate this answer choice because there is new information presented by Dr. Santos.
Answer Choice (C) Similarly to answer choice A, this answer accuses Dr. Santos of weakening rather than strengthening our first speaker’s argument. And if we did not like this in A, we should eliminate answer choice C as well.
Answer Choice (D) It almost feels like these wrong answers say the exact same thing in different ways. Again, this answer choice accuses our second speaker of weakening or taking away from the first speaker’s argument. Like A and C, we can eliminate D for this reason.
Correct Answer Choice (E) This is exactly what we are looking for! This is the only answer choice that correctly highlights the additional positive information Dr. Santos contributes to the first speaker’s position.
Here we have a Method of Reasoning question, which we know from the question stem: “Jermone responds to Ingrid’s claim by…”
After correctly identifying the question type we can use structural analysis to describe the Method of Reasoning used by our speaker. Immediately we should note we have two speakers in our stimulus. That means we need to be on the lookout for two conclusions and two sets of explanations. Our first speaker, Ingrid, lays out a claim; rock has not produced compared to those of the 1940s, because the 1940s records are the ones that continue to be recorded by numerous performers today. Here, Ingrid is assuming a requirement of being a durable song is that it is recorded by numerous performers.
Jerome responds by questioning Ingrid’s assumption. Jerome recognizes that rock songs are only recorded once. However, our second speaker explains this actually reflects the durability of the recordings rather than the lack of popularity of these songs. Jerome challenges Ingrid’s definition of durability to further their own point about the durability of rock music.
Knowing our answer choice will mention the debate surrounding the qualifications of a durable song, we can proceed into answer choice elimination.
Answer Choice (A) We do not have the evidence to suggest that Jermone is intentionally misinterpreting Ingrid’s claim. An answer choice commenting on the intentions of one of the speakers has to follow up with strong confirmatory evidence.
Answer Choice (B) Rather than showing that the claim necessarily leads to a contradiction, Jerome is challenging Ingrid to change the way in which we define durable to begin with.
Answer Choice (C) If our speaker were undermining the truth of Ingrid’s position we would expect Jermone to be challenging the factual content regarding performers in the 1940s. Without questioning the validity of this information we can eliminate answer choice C.
Correct Answer Choice (D) This is exactly what we are looking for. This is the only answer choice that points out how Jermone adjusts the standards for determining what a durable song is.
Answer Choice (E) In order for this answer choice to be correct, we would need to see some indication that Jerome’s argument is based on some sort of character attack. We can eliminate the answer choice Eqwithout this information.
This is a necessary assumption question, though the question stem is quite abrupt and may present some challenges. It’s asking for an assumption, but there is no explicit indication of whether it wants a sufficient or necessary assumption. We have to really understand the nature of our assumptions to see this is necessary rather than sufficient. While it may sound obvious, sufficient assumptions are not necessary: Just because an assumption would be sufficient to validate the argument does not mean that the argument is definitely making that assumption. Necessary assumptions, on the other hard, are necessary. The argument is bound to them and cannot hold without them. Because this question stem is asking for an assumption the argument is definitely and actually making, that is how we know we are looking for a necessary assumption rather than a sufficient.
The stimulus: Well that’s interesting. Caffeine can kill certain insects, or at least their larvae. Now it looks like we have an experiment which is looking into this phenomenon. We see a certain insect die when it ingests some substance which contains caffeine, among other things. We should be drawn to the phrase “in part” because it tells us that there’s other components to whatever we’re feeding these worms. We should immediately question how we know that caffeine, and not some other component of the substance, is responsible. If this argument goes on to draw a conclusion about the effects of caffeine, it’s going to be in trouble.
And that’s exactly what it does in the last line of the sentence, which is our conclusion. The grammar is really convoluted, though, so let’s break it down to determine exactly what the conclusion is. The main body of the sentence is just “This result is evidence for the hypothesis . . .” Which hypothesis? Well, the rest of the sentence specifies which one. But the main part of the sentence is our conclusion: The result is evidence for this hypothesis.
So this doesn’t go as far as it might have. It does not say, “Therefore, caffeine totally evolved as a defense against pests.” That would have been easy to discredit. Rather, it merely says that this experiment is evidence for such a hypothesis. Is it? Well, maybe. What is evidence? Evidence doesn’t have to be conclusive. It only needs to make a proposition more likely to be true. Because there are so many other things they’re feeding to these worms, this is really weak evidence, but despite its weakness, it may nevertheless qualify as evidence. It’s hard to say for sure though. Either way, this opens up a nice big gap with lots of assumptions.
The other observation we might make from this final sentence is the reference to “non-negligible quantities.” Do tea leaves contain non-negligible quantities of caffeine? This argument does not give us an answer. And even if we assume they do, was there enough tea powder in this concoction to deliver a non-negligible dose? Maybe, maybe not. We don’t know. This new term also introduces room for assumptions.
There is a lot going on in this stimulus, and we likely have not have identified every gap. We want to proceed with a POE approach on this one and see what the answer choices might offer up for us to consider.
Answer Choice (A) Sure, maybe. This strengthens the proposition that these plants have insecticidal qualities, but what we care about is caffeine and this does not narrow down which substance in these plants is actually doing the insecticide-ing. Maybe caffeine, maybe something else. Moreover, the hypothesis is addressing caffeine as an evolutionary function, which this does not seem to touch.
Answer Choice (B) This is an interesting suggestion, but it has a problem. Does it have to be “roughly equal” to the amount in the concoction fed to the worms in the experiment? I don’t think so. It could be way higher and we would expect that to do the job.
Answer Choice (C) I can see why this might be attractive. It establishes some link between caffeine producing plants and the pests, and that does appear important to a conclusion about caffeine as an evolutionary response. What if this were not true? What if caffeine producing plants simply don’t grow wherever these pests pose a risk? “Wherever” should give us pause, though. This is a more universal statement than I’m comfortable with here. I think a 99% match would still be pretty compelling. So this gets at something close, but it misses the mark.
Answer Choice (D) Okay. So the specific worm in our experiment is a tobacco pest. What if the tobacco plant doesn’t produce caffeine? That seems like it could be a problem. How can we say caffeine evolved as a defense against these pests if these pests feed off a plant that doesn’t produce caffeine? That might seem seem to break the relevancy of the experiment with any claim about caffeine as an evolutionary mechanism. But does it? It still establishes a sensitivity to caffeine among plant pests. The fact that tobacco may not have evolved that specific defense doesn’t necessarily mean that this can’t support a hypothesis that only relies on the fact that caffeine is an effective pesticide. If D were not true, it would certainly weaken the argument. But I do not think it would destroy it.
Correct Answer Choice (E) This has to be true. No evolutionary pressure; no evolutionary response. If caffeine producing plants have literally never been preyed upon by pests which are sensitive to caffeine, there’s no way this is an evolutionary response. We do need to be a little careful though. Remember, the conclusion is very precise. We are not concluding that these plants evolved caffeine as an evolutionary defense against pests. We are concluding that the experiment with the tobacco worm is evidence that they might have. While this answer needs to be true for this to actually have been an evolutionary response, does it have to be true for this experiment to lend the hypothesis support? Yes. If the hypothesis is disproven, then there is no observation which we would say qualifies as evidence to support it. The hypothesis must remain possible for this experiment to qualify as evidence.
Here we have a flaw question, which we know from the question stem: “The reasoning in the argument is most vulnerable to criticism on which one of the following grounds?” Right away we know our correct answer has to do two things: be descriptively accurate, and describe the flaw of the stimulus. We also know what the wrong answers will do - describe reasoning flaws we’ve seen before, but don’t like up with our stimulus. Once we have a clear understanding of the questrion’s objective, we can proceed into structural analysis of the stimulus.
The speaker begins with a good contender for the conclusion - that weapons production plans are equally wasteful as inflated government spending. We know this is our conclusion because the speaker follows with the support behind it. The government is building a weapons plant that violates 69 laws when it could build a safer one. Huh? What does the passing or not passing of laws have to do with taxpayer dollars? This is where we can spot the assumption being made by the speaker. A comparative conclusion about wasteful spending needs some sort of support that confirms a comparative about wasteful spensing. This argument is flawed because the evidence they give for the conclusion does not actually respond to the issues being presented in this debate.
Knowing our correct answer choice will point out the irrelevant evidence introduced by our speaker, we can proceed into answer choice elimination.
Answer Choice (A) This answer choice is descriptively accurate, but it is not the issue in our stimulus. The argument is flawed because the evidence is irrelevant. Not because the author fails to provide us with some sort of evidence. Whether or not the alternative production site is actually safer does not impact our argument - it adds detail to evidence we already know is irrelevant to the discussion at hand.
Answer Choice (B) This answer choice is not descriptively accurate. In order for our argument to be conceding something we need to see our author agree with a point that does not appear to be completely consistent with their position. Additionally, we do not see evidence that serves to undermine the conclusion in the stimulus. Instead of seeing harmful evidence, we see evidence that really does nothing at all.
Correct Answer Choice (C) This is exactly what we are looking for! This descriptively correct answer choice is the only one that points out the irrelevance of the evidence used in the stimulus.
Answer Choice (D) This answer choice is not descriptively accurate. Suggesting the argument confuses a necessary condition for wasteful research spending means our stimulus presents some sort of requirement for this research. Without any sort of reference to a requirement we cannot call this a conditional reasoning flaw as is suggested by answer choice D.
Answer Choice (E) This answer choice is factually correct, but not the ultimate issue in our stimulus. Our issue is not really that they haven’t explained the comparison between these two institutions. Our problem is that they are supporting the comparison using information completely unrelated to the topic that they are trying to use to compare these groups.