Logical ReasoningDifficulty: Medium

PT8 S4 Q18 Explanation

In order to control the deer

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

TopicsNecessary Assumption

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Stimulus

In order to control the deer population, a biologist has proposed injecting female deer during breeding season with 10 milligrams of a hormone that would suppress fertility. Critics have charged that the proposal poses health risks to people who might eat the meat of treated deer and thereby ingest unsafe quantities of no one would eat even one entire deer a day, the treatment would be safe.

What this question is testing

Necessary Assumption

Your task

Find the assumption the argument requires in order for its conclusion to hold.

Common trap

Answers that would help the argument but aren't strictly required (sufficient, not necessary).

Winning move

Negate each choice — the right one breaks the argument when negated.

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

The question
18.

The biologist’s response to critics of the proposal is based on which one of

Answer choices

  1. Out of Scope: people notified1% picked this

    People would be notified of the time when deer in their area were to be

    Notifying people when deer are treated is not directly related to the argument's concern about the hormone levels after the deer have been treated and people consume them.

  2. Out of Scope: chemical similarity6% picked this

    The hormone that would be injected into the deer is chemically similar to hormones used

    The author hasn't made any assumption that this hormone is similar or different to other things. This answer is speculating a causal backstory for how we have a hormone that can suppress fertility, but it doesn't have to be chemically similar to contraceptives in humans.

  3. Out of Scope: scheduling hunting season2% picked this

    Hunting season for deer could be scheduled so that it would not coincide

    The author is never talking about hunting season at all, let alone making suggestions about the scheduling of it.

  4. Correct65% picked this

    The hormone in question does not occur naturally in the female deer that

    Why this is right

    This has the lovable Defender "not", so we negate it and see if it weakens. If this hormone DOES occur naturally in female deer, would that weaken? Yes! That gives us a way to argue that even though we're only injecting the deer with 10mg, someone who eats the deer may end up ingesting more than that, because they would consume not only the injected hormone but also the naturally occurring hormone. Maybe a thick cut of female deer meat would include 5mg of naturally occurring hormone and 5mg of injected hormone, causing the human to eat a dangerous dose.

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

  5. Out of Scope: most people26% picked this

    Most people do not consider deer meat to be part of their daily diet and eat it

    The word "most" is famously wrong on Necessary Assumption 98% of the time. This argument doesn't care whether 51% or 49% of people consider deer meat to be part of their daily diet.

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