LSAT-Section-1-Logical-Reasoning Section One : Logical Reasoning - Practice Questions

Question 226

Some biologists believe that the capacity for flight first developed in marine reptiles, claiming that feathers are clearly developed from scales. Other biologists rightly reject this suggestion, pointing out that bats have no scales and that nonmarine reptiles also have scales. Those who believe that flight first developed in tree-dwelling reptiles reject the claim that the limbs of land-dwelling reptiles might have developed into wings. They insist that it is more likely that tree-dwelling reptiles developed wings to assist their leaps from branch to branch.

Which one of the following most accurately describes the role played in the passage by the claim that nonmarine reptiles have scales?

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It is cited as evidence against the claim that the capacity for flight first developed in marine reptiles.
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It is cited as evidence against the claim that the capacity for flight first developed in land-dwelling animals.
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It is cited as evidence against the claim that the capacity for flight first developed in tree-dwelling reptiles.
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It weakens the claim that tree-dwelling reptiles were the first kind of reptile to develop the capacity for flight.
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It corroborates the observation that some mammals without scales, such as bats, developed the capacity to fly.

Question 227

Studies have shown that, contrary to popular belief, middle-aged people have more fear of dying than do elderly people.

Each of the following, if true, contributes to an explanation of the phenomenon shown by the studies EXCEPT:

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The longer one lives, the more likely it is that one has come to terms with dying.
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Middle-aged people have more people dependent upon them than people of any other age group.
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Many people who suffer from depression first become depressed in middle age.
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The longer one lives, the more imperturbable one becomes.
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Middle-aged people have a more acute sense of their own mortality than do people of any other age group.

Reference / correct answer:

Many people who suffer from depression first become depressed in middle age.

There are four good explanations for the phenomenon shown by the studies in this argument, so we know that we will have to understand the phenomenon and then jump straight to the answer choices. Just one short sentence to deal with: According to studies, middle-aged people fear dying more than elderly people do. (The phrase “. . . contrary to popular belief” also lets us know that most people think the opposite is true, but that shouldn’t concern us since we’re interested only in the phenomenon itself, not what people believe about it.) Each wrong choice will make it easier to understand why middle-aged folks are more afraid to die than are old people, while the correct choice will not address this question, most likely because it deviates from the scope. And so it does: As there is no stated clear connection between depression and fearing death, the fact that depression often sets in during middle age does nothing to explain the phenomenon described. Depression, while perhaps seemingly relevant at first glance, is actually at least one step removed from the scope here.

Question 228

Historian: Leibniz, the seventeenth-century philosopher, published his version of calculus before Newton did. But then Newton revealed his private notebooks, which showed he had been using these ideas for at least a decade before Leibniz's publication. Newton also claimed that he had disclosed these ideas to Leibniz in a letter shortly before Leibniz's publication. Yet close examination of the letter shows that Newton's few cryptic remarks did not reveal anything important about calculus. Thus, Leibniz and Newton each independently discovered calculus.

Which one of the following is an assumption required by the historian's argument?

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Leibniz did not tell anyone about calculus prior to publishing his version of it.
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No third person independently discovered calculus prior to Newton and Leibniz.
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Newton believed that Leibniz was able to learn something important about calculus from his letter to him.
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Neither Newton nor Leibniz knew that the other had developed a version of calculus prior to Leibniz's publication.
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Neither Newton nor Leibniz learned crucial details about calculus from some third source.

Reference / correct answer:

Neither Newton nor Leibniz learned crucial details about calculus from some third source.

This argument is like a soap opera – lots of back and forth and intrigue over where the true credit for a discovery lies.

The last sentence (set off by “Thus”) contains the author’s conclusion that Leibniz and Newton each discovered calculus independently. What’s the evidence for this claim? Despite Newton’s thoughts on calculus that predate Leibniz’s publication, and even his sharing some of these ideas with Leibniz, close examination reveals that nothing significant was conveyed to Leibniz on the subject. But is this enough to warrant the conclusion that they therefore each discovered calculus independently. Here’s where your ability to form alternatives and to ask yourself “But what if...?” is rewarded: What if someone else contributed to their discovery of calculus? If Leibniz or Newton or both had been given crucial details from some outside source, then the author wouldn’t be able to argue that these two each discovered calculus independently. The author must therefore be assuming that no third party was involved. Whether you thought of this on your own, or recognized the validity of the option [Neither Newton nor Leibniz learned crucial…]. when you saw it, it’s all the same – another point on the board.

LSAT-Section-1-Logical-Reasoning – Section One : Logical Reasoning