Logical ReasoningDifficulty: Medium

PT15 S2 Q3 Explanation

A certain strain of bacteria

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

TopicsStrengthen

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Stimulus

A certain strain of bacteria was found in the stomachs of ulcer patients. A medical researcher with no history of ulcers inadvertently ingested some of the bacteria and within weeks developed an that the bacteria strain induces ulcers.

What this question is testing

Strengthen

Your task

Find the choice that makes the argument's conclusion more likely to be true.

Common trap

Answers that are consistent with the argument but add no real support, or that strengthen a claim the argument doesn't make.

Winning move

Locate the gap between evidence and conclusion, then pick the choice that closes it.

Reading along? Open the full official question in LawHub — we show a fragment here and keep the reasoning in our own words.

The question
3.

Which one of the following, if true, most supports the

Answer choices

  1. Irrelevant Comparison2% picked this

    People who have the bacteria strain in their stomachs have been found to have no greater incidence of kidney disease than do

    Whether the bacteria is related to kidney disease has no impact on whether the bacteria causes ulcers. The issue at hand is the causal relationship between the bacteria and ulcers, making kidney disease irrelevant here.

  2. No Impact16% picked this

    The researcher did not develop any other serious health problems within a year after ingesting

    This argument doesn't care about other health issues that might result from the bacteria. It's only concerned with whether ulcers are an effect of the bacteria.

  3. Opposite Impact0% picked this

    There is no evidence that the bacteria strain induces ulcers in

    This makes it a lot less plausible that the bacteria causes ulcers, so this would weaken.

  4. No Impact4% picked this

    The researcher is a recognized expert in the treatment of diseases

    The expertise of the researcher in stomach diseases is irrelevant to the argument's causal link between bacteria and ulcers. The focus is on the effect of the bacteria, not the researcher's qualifications.

  5. Correct78% picked this

    A study of 2,000 people who do not have ulcers found that none of these people had the

    Why this is right

    Wow, it's the classic "No Cause, No Effect" strengthener (the most common way to strengthen an Explain Curious Fact argument). These 2000 people didn't have the bacteria and didn't have ulcers, providing more data points that strengthen the covariation between having/not-having the bacteria and having/not-having ulcers.

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

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