Logical ReasoningDifficulty: Hard

PT10 S4 Q17 Explanation

The Gulches is an area

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

TopicsParadox

Keep going in LSAT Lab

  • Save & drill this skill — build targeted practice sets from questions like this one

  • Video walkthroughs — watch every question solved step by step

  • 81 official LSATs — as questions, timed sections & full-length tests

Start practicing free

Free to start

Full official LSAT questions are available through LawHub. This page provides LSAT Lab's explanation, strategy, and review tools without republishing the full official question.

Stimulus

The Gulches is an area of volcanic rock that is gashed by many channels that lead downhill from the site of a prehistoric glacier to a river. The channels clearly were cut by running water. It was once accepted as fact that the cutting occurred gradually, as the glacier melted. But one scientists still do not know of a process that can melt so much ice so quickly.

What this question is testing

Paradox

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
17.

Which one of the following, if true, most helps to resolve the apparent paradox

Answer choices

  1. Trap13% picked this

    Ripples, which indicate that the channels were cut by water, have been discovered in the

  2. Trap2% picked this

    The Gulches is known to be similar in certain respects to many other

  3. Trap7% picked this

    More than one glacier was present in the area during

  4. Trap10% picked this

    Volcanic rock is more easily cut by water than are other

  5. Correct68% picked this

    Scientists now believe that the prehistoric glacier dammed a source of water, created a huge lake in the

    Why this is right

    Answer E is correct.

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

Continue the review in LSAT Lab

Save this question, watch the video walkthrough, and drill similar questions in your LSAT Lab account.

Save and practice this skill
LSAT Lab

Turn this review into a targeted study plan.

Save this question, drill more like it, watch the video walkthrough, and track your progress in your LSAT Lab account.

Start practicing free