Q16 - The Gulches is an area

[sr]

How can answer choice D be correct? Answer choice D talks about water on rock, but the stimulus is specifically about ice, not rock.

[timmydoeslsat]

How can answer choice D be correct? Answer choice D talks about water on rock, but the stimulus is specifically about ice, not rock.

The stimulus is about how an area of rock has channels or gashes running through it that was clearly caused by running water. It was initially believed that these gashes in the rock were caused by a gradual melting of a glacier. However, a geologist hypothesized that these gashes were caused by a big flood. There was physical evidence that showed the gashes formed quickly.

This allows us to make (D) a supported statement based on the text. We can infer that the ability to determine that a gash was formed quickly in a rocks gives us an opportunity to know that the effects of water on rocks vary with speed. If it were not the case, how would it be determined that the gashed rock was formed quickly?

[ManhattanPrepLSAT1]

Great technique Timmy in turning it around and asking "what if it were not the case?" You'll find this technique frequently useful when the question asks for "what is most strongly supported?" Because of the similarity between question types, folks often want to do this on Must be True questions. You'll find, however, the technique less useful on such questions.

Nice work!

[jh2352]

Can someone explain why the didn't pick the other answer choices.

[hana.kid]

I'll give it a shot! Not sure if what I've got down is correct, so maybe an LSAT expert can chime in?

(A) - detail creep. This one is super tempting because of the "channels clearly were cut by running water" bit, but you also have you keep in mind that we're talking about The Gulches, not all areas of volcanic rock.
(B) - The stimulus only tells us that the channels lead to a river, but nothing else. So the river may or may not have been there before the channels.
(C) - detail creep. The stimulus says scientists don't know of a process that can melt so much ice, not the amount of heat required.
(E) - I think this choice is wrong for a couple reasons. There's nothing about geologists being "compelled." And the scientists don't reject physical evidence, they actually accept it since they accept the flood theory.

[kkate]

Great technique Timmy in turning it around and asking "what if it were not the case?" You'll find this technique frequently useful when the question asks for "what is most strongly supported?" Because of the similarity between question types, folks often want to do this on Must be True questions. You'll find, however, the technique less useful on such questions.

Can someone elaborate on "what if it as not the case" strategy? Thanks!

[a8l367]

If it were not the case, how would it be determined that the gashed rock was formed quickly?

By some radioactive analises or whatever. Where do you get that speed is the only evidence that could lead to the "formed quickly" conclusion?

IMHO "channels ... show physical evidence of having been formed quickly" => "physical effects of water on rock vary with the speed with which those effects are produced" has serios gaps. What if water is not the case, but some dirt in water cause those efects? etc.

[AnnaC659]

Would (E) be correct if it said "scientists" instead of "geologists"?

[ohthatpatrick]

Geologists are scientists, so switching it to say scientists wouldn't affect the burden of proof here.

Just look out for strong language.
(A) ONLY this can cause that
(B) This DIDN'T EXIST AT ALL before that happened
(C) This CANNOT do that
(E) These are COMPELLED do to that

(D) one thing HAS AN EFFECT on another thing


Beyond that, (E) is more or less contradicted by the passage. Scientists originally rejected physical evidence because of the unexplainable melting mechanism, but now they apparently trust that physical evidence, even though they still don't know the unexplained melting mechanism.

If Geologists were COMPELLED to reject like they originally did,
they wouldn't be able to accept like they currently are.