Logical ReasoningDifficulty: Hard

PT127 S1 Q7 Explanation

Two different dates have been

A free, expert breakdown of this official LSAT Logical Reasoning question.

TopicsMost Supported

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Stimulus

Two different dates have been offered as the approximate end point of the last ice age in North America. The first date was established by testing insect fragments found in samples of sediments to determine when warmth-adapted open-ground beetles replaced cold-adapted arctic beetles. The second date was established by testing pollen grains The first date is more than 500 years earlier than the second.

What this question is testing

Most Supported

Your task

Break the argument into its conclusion and evidence, then do exactly what the question stem asks with that structure.

Common trap

Answers that sound relevant to the topic but don't connect to the argument's actual reasoning.

Winning move

Predict what a right answer must do, then test each choice against the conclusion-evidence gap.

Reading along? Open the full official question in LawHub — we show a fragment here and keep the reasoning in our own words.

The question
7.

The statements above, if true, most strongly support which one of the following conclusions about the last ice age and its

Answer choices

  1. Too Strong: ceased to inhabit5% picked this

    Toward the end of the ice age, warmth-adapted open-ground beetles ceased to inhabit areas where the predominant tree

    This sounds stronger than anything we learned. Can we say that there were no warmth-adapted beetles in areas where the predominant tree cover consisted of spruce forests? This answer is jamming the two sentences together in a way that goes beyond the "500 years" comparison we know. The first date came by studying dirt (in some area that would be cold during an ice age but warm once the ice age ended). They studied the transition from when a cold-weather species lived somewhere to when a warm-weather species started living there. We don't know if these sediment samples were from a spruce forest at all.

  2. Unsupported11% picked this

    Among those sediments deposited toward the end of the ice age, those found to contain cold-adapted arctic beetle fragments can also be

    Just like (A), this is trying to jam together the sediment / beetle fact with the pollen grain / spruce fact, but the only means we have to compare them is the 500 year fact. This answer, like (A), is acting as though these two tests were conducted in the same area, but the paragraph never said any such thing. We have no reason to think that the beetle-test was done in the same area as the pollen grain testing, so we have no way to support that you'd find cold-beetle fragments and pollen grains in the same area.

  3. Out of Scope: advance8% picked this

    Ice masses continued to advance through North America for several hundred years after the end

    When an ice age begins, the polar ice caps steadily advance outward from the poles (the ice caps from the North Pole extend down through Canada to the northern latitudes of America). They get as far south as the new ice age climate will allow, then they pretty much stay there until the climate starts to warm again. When an ice age ends, the polar ice caps steadily retreat backwards towards the poles. The fact that warm-beetles came out 500 years before "ice masses yielded to spruce forests" implies that when warm-beetles came back, the ice caps had not yet receded towards the North Pole. This answer, meanwhile, is saying that the ice caps were still advancing southward through North America. We have no evidence for that.

  4. Too Strong: died out13% picked this

    The species of cold-adapted arctic beetle that inhabited areas covered by ice masses died out toward the end

    During an ice age, as the polar ice caps expand southward, the arctic habitat expands. A polar bear might end up all the way down where New York is. But when the ice age ends, the polar ice caps recede back towards the poles, shrinking the arctic habitat, forcing the cold-adapted animals to migrate back north where it's cold enough for their liking. The first date came from scientists looking at a certain area like New York that is cold during an ice age but warm otherwise, so that they could see when it went from being a place where cold beetles wanted to live to being a place where warm beetles wanted to live. The fact that warm beetles started living somewhere just means that that area because too warm for cold beetles, but that doesn't mean all cold beetles died out. Their habitat just shrunk, so they would have headed north to where it was still cold.

  5. Correct64% picked this

    Toward the end of the ice age, warmth-adapted open-ground beetles colonized the new terrain opened to them faster than soil changes and

    Why this is right

    This plays off the 500 years earlier comparison fact we know: warm-beetles came back before spruce forests came back. It tries to make itself unappealing by getting specific about how a forest re-establishes itself following an ice age (soil changes / seed dispersion). That part goes beyond anything we were told, but this answer is still the most supported.

    Skill tested: Most Supported · how this choice captures the argument's function is the move to repeat next time.

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