Logical Reasoning

PT117 · S2 · Q15 According to current geological theory

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According to current geological theory, the melting of ice at the end of the Ice Age significantly reduced the weight pressing on parts of the earth’s crust.

Conclusion (Therefore)

It is likely that the melting of the ice at the end of the Ice Age contributed to earthquakes that racked Sweden during that time period.

Evidence

The melting of ice at the end of the Ice Age reduces the weight pressing on the earth's crust in certain spots, which leads to lasting cracks in the crust at these spots.

Evaluate

The conclusion is saying that melting contributed to earthquakes.

The evidence lays out a mini-Causal Chain that gets us from melting to cracks.

Melting → reduced weight → cracks of ice or parts of crust in crust

In order to get from melting to earthquakes, there's still a missing link in the causal chain:

cracks → earthquakes? in crust

Goal

If this is testing a Missing Link, then we want an answer that's saying something like . Or we could pick anything else that increases the plausibility that the melting of ice contributed to these earthquakes (for example, ).

Usually, with causal conclusions, we could also consider strengthening by ruling out an Alternate Explanation (for the severe earthquakes, in this case).

But the author didn't say the quakes were caused by melting ice, rather that melting ice is one of the causes. So Alternate Explanations technically don't matter here.

15.

Which one of the following, if true, most strengthens the argument above?

  1. The earth’s crust tends to

    No Impact

    We already know that a reduction in pressure from melted ice leads to cracks. This answer is saying that other changes in pressure could also lead to cracks, but why would we care? That wouldn't have anything to do with the author's storyline, so it wouldn't be strengthening her storyline. We need to know whether cracks, caused by the change in pressure from melting ice, lead to earthquakes.

    17% picked this

  2. There are various areas in

    Too Weak

    The author is assuming that there was some melting ice close enough to Sweden that it led to a change in pressure, and thus to cracks, and thus to severe earthquakes. Her causal story assumes there are some cracks near Sweden (close enough to cause earthquakes there). But this answer is saying there are cracks somewhere in Northern Europe, from some time period (might be end of Ice Age, might not). So this is too wishy-washy to tell us anything.

    4% picked this

  3. Evidence of severe earthquakes around

    No Impact

    This doesn't seem to have any impact on making the "melting ice" hypothesis more or less plausible. If we knew that there were severe earthquakes and melting ice near the end of the Ice Age in northern Canada, then that would strengthen the notion that melting ice is connected to these earthquakes. But this answer just tells us that there were also earthquakes elsewhere.

    9% picked this

  4. Correct

    Severe earthquakes are generally caused

    Why this is right

    This helps us with our missing link in the causal chain. The author is trying to prove a causal connection between melting ice and severe earthquakes. melting ----------------------> severe ice quakes She established this so far melting ----> less ---> cracks ice pressure So she needs to establish that "cracks lead to quakes", and that's what this answer provides.

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

    69% picked this

  5. Asteroid impacts, which did occur

    Weakens, if anything

    This seems to point out a potential Alternate Explanation for the earthquakes, which would weaken. (As discussed earlier, technically an Alternate Explanation doesn't really weaken this argument, because the conclusion isn't saying that the earthquakes were only caused by melting ice, but still, this feels more like weaken than like strengthen).

    1% picked this

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