Logical Reasoning

PT127 · S2 · Q8 This boulder is volcanic

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This boulder is volcanic in origin and yet the rest of the rock in this area is sedimentary.

Evidence

This boulder is volcanic in origin and yet the rest of the rock in this area is sedimentary.

This area was covered by southward-moving glaciers during the last ice age.

Conclusion

This boulder was probably deposited here, hundreds of miles from its geological birthplace, by a glacier.

Evaluate

Since glaciers once covered the area it is plausible that the bolder was deposited here by a glacier. For that to be the case there would need to be a source of volcanic rock north of the boulder.

8.

Which one of the following, if true, most seriously undermines the conclusion drawn in the argument above?

  1. Most boulders that have been

    Out of Scope

    Other boulders are not relevant to the argument.

    17% picked this

  2. The closest geological source of

    Irrelevant Relationship

    The boulder need not have traveled here from the nearest geological source.

    9% picked this

  3. The closest geological source of

    Irrelevant Relationship

    The boulder need not have traveled here from the nearest geological source.

    6% picked this

  4. Correct

    There are no geological sources

    Why this is right

    This weakens the argument by attacking the argument’s assumption.

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

    66% picked this

  5. No other boulders of volcanic

    Out of Scope

    Other boulders are not relevant to the argument.

    3% picked this

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