According to current geological theory, the melting of ice at the end of the Ice Age significantly reduced the weight...

llowe on January 8, 2020

Answer Choice C

Can someone please explain why C is incorrect? The conclusion of the argument appears to be "it is likely that the melting of the ice contributed to these earthquakes" (i.e. the earthquakes in Sweden). I thought a way to strengthen a cause and effect argument is to show a case with the same cause and same effect, which seems to kind of happen in C. Answer choice D seems to almost weaken the argument to me by showing an alternate cause for the earthquakes (i.e. the cracks in the earth's crust cause the earthquakes). Thanks!!

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Annie on January 9, 2020

Hi @llowe,

This argument is asking you to pick the answer choice which most strengthens the argument. I like to think of this as if the answer choices are extra premises, and you're looking for the one that fits in best with the argument. Here's a break down of the argument:

Premise 1: Under current theories, the melting ice at the end of the Ice Age reduced the weight pressing on parts of the earth's crust.
Premise 2: This led to lasting cracks in the earths crust in some places under stress from pressure below.
Premise 3: At the end of the Ice Age, Sweden experienced several earthquakes.
Premise 4: ??
Conclusion: Therefore, it is likely that melting ice contributed to these earthquakes.

Now, try to see if there are any gaps in the argument you can spot before turning to the answer choices. To me, I see a disconnect between Premise 3 and the conclusion. Do we know that earthquakes have to do with this melting and the weight on the earth? We haven't been given any information connecting these two ideas.

Turning to the answer choices:
(A) is incorrect. It does not provide information connecting the idea that Sweden had earthquakes with the idea that the melting ice was involved. This just talks about the earth's crust cracking, but we don't know that that has to do with an earthquake.

(B) is incorrect. This has nothing to do with Sweden or the conclusion.

(C) is incorrect. This relates to Canada, not to Sweden.

(D) is correct. This answer choice fills in the gap we identified above. Premises 1 and 2 tell us that the melting ice led to cracks in the earths crust. Then Premise 3 and the conclusion tell us that Sweden experienced earthquakes and this was related to the ice melting. This answer choices fills in the gap between these ideas and tells us that cracks in the earth's crust lead to earthquakes.

(E) is incorrect. This is irrelevant to the argument.