Logical ReasoningDifficulty: Easy

PT11 S2 Q1 Explanation

Sea turtles nest only

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

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Stimulus

Sea turtles nest only at their own birthplaces. After hatching on the beach, the turtles enter the water to begin their far-ranging migration, only returning to their birthplaces to nest some 15 to 30 years later. It has been hypothesized that newborn sea turtles learn the smell smell that stimulates the turtles to return to nest.

What this question is testing

Weaken

Your task

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

Common trap

Answers that look negative but attack a claim the argument never relied on.

Winning move

Find the assumption the argument depends on, then pick the choice that undermines 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
1.

Which one of the following, if true, would cast the most serious doubt on the hypothesis

Answer choices

  1. No Impact4% picked this

    Beaches on which sea turtles nest tend to be in secluded locations such

    The seclusion of the beaches where turtles nest does not inform us about whether smell is the mechanism guiding turtles back to their birthplaces, or something else.

  2. No Impact9% picked this

    Sea turtles exposed to a variety of environments under experimental conditions preferred the environment that contained sand

    This fact seems to suggest that sea turtles have an attraction to the environment where they were born. But we already knew that. After all, they return there after 15-30 years. We're trying to figure out how they find their way back, and this isn't weighing in on whether it's via smell or via some other mechanism.

  3. No Impact1% picked this

    Electronic tags attached to sea turtles did not alter their

    The fact that electronic tags do not alter nesting patterns doesn't provide any information about whether the turtles rely on smell or something else to return to their birthplaces.

  4. Opposite Impact1% picked this

    Unlike other types of turtles, sea turtles have a well-developed sense

    This would lend plausibility to the hypothesis that the turtles smell their way home, which is the opposite of what we're trying to do.

  5. Correct86% picked this

    Sea turtles that had their sense of smell destroyed by exposure to petroleum products returned to nest

    Why this is right

    If sea turtles that had their sense of smell destroyed still returned to nest at their birthplaces, it undermines the idea that smell is the key factor guiding them back. It's essentially an Effect w/o Cause weakener (they're able to find their way home even though they're not capable of smelling home).. This suggests that other mechanisms must be responsible for their navigational abilities, casting doubt on the hypothesis.

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

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