Let’s start by looking at the stimulus. It gives us a causal relationship that the cause of the bonobos eating the leaves during the rainy season is the avoidance of GI worms. Gross, but clear.

We want to strengthen that causal relationship. We can do that by eliminating an alternate cause, showing the cause occurs when the effect occurs (and vice versa), showing the relationship is not reversed, and backing up the data used to make the causal conclusion.

For answer choice (A), it doesn’t address the causal relationship, because we don’t know the effect on the GI worms for the other plants.

For answer choice (D), it also doesn’t address the causal relationship between leaves and GI worms. It just talks about leaves being easier to eat whole. But we don’t know the leaves have to be eaten whole.

Answer choice (E) does strengthen our causal relationship. It tells us when the cause occurs (leaf eating during the rainy season) the effect is also present (GI worms that can cause infection).

It it obvious that the author claims that reduction in total miles traveled is a better option overall than imposing safety measures.

This argument involves the concept of numbers and percentages but also involves causal reasoning. These two concepts often overlap, as somebody making an argument is often trying to provide a reason/cause to explain an unusual statistic.

In this argument, we are told that “Over the last year alone, the paper has published over five times as many movie reviews as reviews of live plays.” This is the premise/data, and there’s no reason to suspect that it is factually incorrect.

The next question is why is the paper publishing over five times as many movie reviews (i.e. what is causing this to happen?).

The author concludes that it must be due to a bias of the arts section of the newspaper toward movies and against local theater. While this is one possible explanation/cause, there certainly could be others.

There are a number of specific ways to weaken a causal argument that are covered in lesson 3 of our LSAT course and in chapter 8 of The Logical Reasoning Bible.

The number one way to weaken a causal argument is to find an alternate cause to explain the effect.

Here, a straight-forward prephrase that would explain why the newspaper reviews a lot more movies is that maybe a lot more movies come out each year than the number of local theater shows. This would be a reasonable explanation other than bias and is what we get in Answer B.

The problem with Answer C is that it doesn’t weaken the conclusion that the newspaper is biased toward movies and in fact could actually strengthen it. At first glance, you may think that the fact that the newspaper has five movies critics and only 1 theater critic provides an alternate cause for why they have more movies reviews (because they just have more staff to cover movies).

But the problem is that you have to ask yourself “why does the newspaper have 5 movie critics and only 1 theater critic?” We don’t know, but that could very possibly be due to the bias of the newspaper. And, assuming movie critics generally prefer movies to theater (which seems pretty reasonable), then having 5 movie critics and only 1 theater critic would suggest that the newspaper’s art section staff may very well be biased toward movies.

The argument concludes that this newspaper is biased towards movies and against local theater based on the fact that there were over five times as many movie reviews as local theater/live play reviews.

Answer E only tells us that the number of reviews of live plays was more last year than two years ago. At first, this might seem to suggest a positive trend toward reviewing live plays for the newspaper as the number is growing from the prior year.

However, the argument is based on the large discrepancy between the number of movie reviews and the number of local theater reviews, so even if the local theater reviews increased in the past year (we don’t know how much, possibly only by one or two), the newspaper could still be biased as shown by the much more frequent coverage of movie reviews.

The real problem with this numbers-based argument is that we don’t know how many local theater performances there are each year. If there are only a few of them performed each year, then that would explain why the newspaper only covers a few because there’s a very limited selection to cover. This is best addressed in Answer B.

The conclusion of the argument in the stimulus appears in the second half of the final sentence, “our museum should return the artifacts.” This is the conclusion that everything else in the argument is there to support.

Answer E is describing the principle that the argument relies on to reach the conclusion that the museum should return the artifacts. So Answer E is describing a premise of the argument rather than its conclusion.

Usually, the conclusion for most Main Point questions is not found at the end of the argument because that is where most people expect it to be. This question is unusual in that the conclusion does appear at the end.

Demk26: Good diagramming! You are correct that answer choice (A) is a Supporter Assumption that is filling in the gap in the argument. But the gap here is a little more nuanced than you have diagrammed. As Brook described above, the gap is more so the jump from the premise that “some” of their predictions are wrong to the conclusion that they are not truly precognitive. Answer choice (A) provides us with that link between the premise and the conclusion because it states that:

Truly precognitive  ALL predictions accurate
Contrapositive: ALL predictions accurate  Truly precognitive

Some predictions do not come to pass = ALL predictions accurate

Therefore, answer choice (A) fills in the gap between the premise and the conclusion.

The main problem with the stimulus is that the conditional and its contrapositive do not lead to the conclusion that some of the characters aren’t truly precogs. What we know is that sometimes a foreseen event doesn’t occur, so sometimes there wasn’t accuracy. But the first sentence of the stimulus only said that a precog must be able to accurately perceive future events. The conclusion of the stimulus is a little bit like claiming that Steve Curry isn’t a free throw shooter because he sometimes misses. It’s silly. So to make the stimulus work, we have to deal with that difference between ability and certainty. That’s what (A) does. I don’t know whether that’s mechanical enough for you, but it’s the way I see the analysis.

Just responding to confirm that your thinking on this question is spot on. This is a resolve EXCEPT question, so any answer choice that might contradict the information we’re given (i.e. deaths might increase if workplace safety resources declined) cannot resolve the issue and would therefore be the correct answer in this case. The other four answer choices offer relatively weak circumstantial explanations, but that’s perfectly acceptable when we have one answer choice that would work in the opposite direction.

For the most jobs, there is a certain percentage of accident rates each year. For some jobs, let’s say Alaskan crab fisherman, there is a higher accident rate than a job like insurance salesman. If we’re talking about the overall percentage of workplace accidents here, lowering the overall number of employees who are doing dangerous jobs like Alaskan crab fishing is not only going to lower the raw number of employees injured, it’s also going to lower the percentage of people injured on the job, because the biggest contributors to that overall injury rate have lowered their contributions.

Keep in mind, this entire question is talking about all employment as a whole, so the injuries coming out of very dangerous sectors represent a bigger portion of the overall pie than safer jobs.

The author concludes that a difference in parasitic infection rates between migrating and non-migrating butterflies is due to migration. Why couldn’t it be the other way around? In fact, the stimulus even says that infected butterflies can have deformities that interfere with flight. It makes at least as much sense as the author’s conclusion to think that instead the butterflies that couldn’t fly right didn’t migrate, so the difference in infection rates is the cause of differences in migration rather than vice versa. This precisely is answer choice (D).

The size of the population does not affect the percentage infected, so answer choice (C) is itself confusing numbers and percentages. Percentages are relevant here, and it was not a flaw in the reasoning to stick with percentages. There is no need to provide additional information about raw numbers.

The stimulus is basically telling us two things: 1) Birds need to stabilize in their wings in order to fly; and 2) the only thing in the bird body that could stabilize the wings is a certain ligament.

We can conclude that the ligament is the MEANS by which a flying bird stabilizes its wings. That’s answer choice E.

However, we cannot conclude anything about the REASON why a bird’s wings have to be stabilized in the first place. That would likely have something to do with force and physics and other science-y things that the information presented in the stimulus doesn’t cover, and we’re therefore not expected to know anything about. So that knocks out answer choice B as out of scope.

There are three contending factors given in the stimulus: budget, “majesty” and convenience to commuters. The budget can’t be increased, and the current design is majestic, but lacks a feature that is convenient to commuters. Without an increase in the budget, we can’t have both a majestic station and a convenient one, so the stimulus is arguing that the design should be made less majestic in order to accommodate the feature that will make it more convenient. We’re then tasked with strengthening this argument using a principle, which I prephrased as “Commuter convenience is a greater priority than majesty;” note the comparison element, which is crucial for allowing the argument to effectively choose one over the other in a situation where we can’t have both.

(A) is effectively a restatement of part of the conclusion (“building a more modest station”) rather than an actual reason/premise to do so. Again, the logical gap in the stimulus that we need to fill is the prioritization of commuter convenience over station majesty. (A) doesn’t do this, while (C) does, making (C) the correct answer choice.

When you approach a fill-in-the-blank question, you need to determine what part of the argument needs to be supplied (for example, a premise or a conclusion). In this case, the question stem asks you to strengthen the passage by completing it, so we know that we need to find an additional premise.

The stimulus tells us that diagnosed strokes are mostly left-side strokes, and concludes that right-side strokes are less likely to be diagnosed. The answer will explain why we can reach that conclusion.

(B) says that strokes are about as common on the left side as on the right side. That would explain the conclusion that right-side strokes aren’t being diagnosed. Put differently, if strokes are equally common on the left and right side, but the diagnoses are of left-side strokes, that means we’re missing diagnosis of the right side strokes.

(D) draws a difference between right side and left side strokes without offering any support for the conclusion that right side strokes are not diagnosed as frequently as they occur. Just because the symptoms are missing doesn’t mean that the doctors are failing to diagnose right-side strokes.