Logical Reasoning

PT119 · S4 · Q24 Biologist: We know the following

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

  • 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

Biologist: We know the following things about plant X. Specimens with fuzzy seeds always have long stems but never have white flowers.

Statements

Conditionals (always = right side)

Fuzzy seeds → Long Stems Fuzzy seeds → No White Flowers Curled leaves → White flowers Thorny seedpods → Curled leaves

This specimen: Long Stem, Curled Leaves

Evaluate

There are four conditionals, and there are some overlapping terms (2 Fuzzy Seeds, 2 Curled Leaves, 2 White Flowers), so some of them probably chain together.

But rather than chain everything together, and possibly waste time, let's be goal driven and just go fact hunting for the two things we know about this specimen: Long Stem and Curled Leaves.

Fuzzy seeds → Long Stems Fuzzy seeds → No White Flowers Curled leaves → White flowers Thorny seedpods → Curled leaves

The only useful conditional there is the 3rd one. Knowing the outcome of a conditional tells you nothing. But knowing the trigger of a conditional gives you extra information.

If they have curled leaves, then we know for sure they have white flowers. White flowers is mentioned in another rule. Does that rule tell us anything?

Fuzzy seeds → No White Flowers

Yes, because if we contrapose this, it says

White Flowers → No Fuzzy Seeds

So we know that this specimen has no fuzzy seeds. There's another rule about fuzzy seeds. Does that tell us anything?

Fuzzy Seeds → Long Stems

Nope. That rule is triggered when a plant does have fuzzy seeds, not when it doesn't.

Goal

So we figured out that this specimen as white flowers and doesn't have fuzzy seeds.

If we were chaining together all the rules, we'd have these chains:

Thorny → Curled → White → No Fuzzy Seedpods Leaves flowers Seeds

Long Stems Fuzzy → and Seeds No White → No Curled → No Thorny Flowers Leaves Seedpods

24.

From the biologist's statements, which one of the following can be properly inferred about the specimen of plant X in the biologist's garden?

  1. It has white flowers and

    Unsupported: thorny seedpods

    We know that this specimen has a long stem (which leads nowhere) and curled leaves, which leads to white flowers and no fuzzy seeds. We don't know whether or not it has thorny seedpods. Thorny → Curled → White → No Fuzzy Seedpods Leaves flowers Seeds Long Stems Fuzzy → and Seeds No White → No Curled → No Thorny Flowers Leaves Seedpods

    12% picked this

  2. It has white flowers but

    Unsupported: thorny seedpods

    We know that this specimen has a long stem (which leads nowhere) and curled leaves, which leads to white flowers and no fuzzy seeds. We have no idea whether it has thorny seedpods or not. Thorny → Curled → White → No Fuzzy Seedpods Leaves flowers Seeds Long Stems Fuzzy → and Seeds No White → No Curled → No Thorny Flowers Leaves Seedpods

    3% picked this

  3. Correct

    It has white flowers but

    Why this is right

    We know that this specimen has a long stem (which leads nowhere) and curled leaves, which leads to white flowers and no fuzzy seeds. Thorny → Curled → White → No Fuzzy Seedpods Leaves flowers Seeds Long Stems Fuzzy → and Seeds No White → No Curled → No Thorny Flowers Leaves Seedpods

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

    64% picked this

  4. It has fuzzy seeds and

    Unsupported: thorny seedpods

    We know that this specimen has a long stem (which leads nowhere) and curled leaves, which leads to white flowers and no fuzzy seeds. We have no idea whether it has thorny seedpods or not. Thorny → Curled → White → No Fuzzy Seedpods Leaves flowers Seeds Long Stems Fuzzy → and Seeds No White → No Curled → No Thorny Flowers Leaves Seedpods

    18% picked this

  5. It lacks both white flowers

    Double-Contradicted

    We know that this specimen has a long stem (which leads nowhere) and curled leaves, which leads to white flowers and no fuzzy seeds. Thorny → Curled → White → No Fuzzy Seedpods Leaves flowers Seeds Long Stems Fuzzy → and Seeds No White → No Curled → No Thorny Flowers Leaves Seedpods

    3% picked this

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