Logical Reasoning

PT2 · S4 · Q18 Some cleaning fluids

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Some cleaning fluids, synthetic carpets, wall paneling, and other products release toxins, such as formaldehyde and benzene, into the household air supply.

Premise

Some products release toxins like formaldehyde and benzene into household air. This is a problem in well-insulated houses (which trap toxins). Houseplants remove some household toxins from the air. In one test, 20 plants eliminated formaldehyde from a small, well-insulated house.

Setup

Someone living in a small, well-insulated house with toxin-releasing products places plants like those tested.

Evaluate

What is guaranteed? Plants remove "some" toxins, and the test specifically showed 20 plants eliminating formaldehyde. So if formaldehyde is in the air, the plants will reduce it. We cannot guarantee benzene is removed (the test only showed formaldehyde), and we cannot guarantee the air becomes "safe" overall (other toxins may remain).

Goal

Find a modest, narrowly-scoped inference: if formaldehyde is in the air, its level decreases.

18.

Which one of the following can be expected as a result?

There will no longer be
Too Strong
The stimulus never says plants remove enough toxins to eliminate the need for ventilation. Plants remove "some" household toxins; well-insulated houses still have toxin-releasing products (cleaning fluids, paneling, etc.); and the formaldehyde test only addresses one toxin. Saying ventilation is no longer necessary goes far beyond what the stimulus supports.
1% picked this
The concentration of toxins in
Contradicted
The stimulus directly tells us plants remove some toxins, and 20 plants eliminated formaldehyde in the test. So toxin concentrations are not going to remain the same — at minimum, formaldehyde will decrease. This contradicts the stimulus.
0% picked this
The house will be warm
Too Strong
"Safe air supply" overshoots. The stimulus only supports that plants remove some toxins — and the test specifically showed only formaldehyde elimination. Benzene and any other untested toxins might still pose a danger. We cannot conclude the air is safe.
4% picked this
Correct
If there is formaldehyde in
Why this is right
This is the modest inference the stimulus actually supports. The test showed 20 plants eliminating formaldehyde in a small, well-insulated house — which is precisely the setup the question describes. So if formaldehyde is in the air, plants will reduce it. The conditional ("if there is formaldehyde") and the modest claim ("its level will decrease") match exactly what the stimulus guarantees.
Skill tested: Must be True · how this choice captures the argument's function is the move to repeat next time.
85% picked this
If formaldehyde and benzene are
Term Shift
This talks about the quantities released decreasing. But plants do not affect the rate at which products release toxins — plants pull toxins out of the air after release. The stimulus is about removing toxins from the air supply, not slowing the source. This shifts what plants are claimed to do.
9% picked this

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