Logical ReasoningDifficulty: Easy

PT154 S4 Q12 ExplanationA lichen is made up of

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

TopicsMost Supported

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Stimulus

A lichen is made up of a photosynthetic organism and a fungus growing in symbiosis on a solid surface. Lichens absorb minerals from air and rainwater but also from the surfaces on which they grow; they cannot excrete the elements they absorb. Some varieties are very vulnerable air. Such compounds can damage both of the symbiotic partners.

What this question is testing

Most Supported

Your task

Break the argument into its conclusion and evidence, then do exactly what the question stem asks with that structure.

Common trap

Answers that sound relevant to the topic but don't connect to the argument's actual reasoning.

Winning move

Predict what a right answer must do, then test each choice against the conclusion-evidence gap.

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

The question

12.

Which one of the following is most strongly supported by the

Answer choices, explained

Unsupported Causality5% picked this
Lichens would not be vulnerable to toxic compounds if they could excrete the elements
We're never told that some lichens are vulnerable to toxic compounds because they can't excrete the elements they absorb. This answer does reference two of the statements in the stimulus, but they're separate statements. The stimulus doesn't clearly connect these statements in any way that indicates a causal or conditional relationship.
5%
Too Strong Out of Scope1% picked this
The return of lichens to a region indicates that the air quality
Lichens disappearing or returning to a region is outside the scope of the information we're given. We're told that some varieties are very vulnerable to toxic compounds, which can damage the lichens, but this doesn't necessarily mean that they will disappear.
1%
Too Strong Out of Scope4% picked this
The absence of lichens in a region indicates that the air is probably polluted
As with answer choice B, this answer is, at best, too strong. We can't conclude that pollution will cause lichens to completely disappear. We only know that pollution can damage lichens. An absence of lichens in a region is really outside the scope of the information we're given.
4%
Out of Scope2% picked this
The photosynthetic organism and the fungus that make up a lichen can also thrive independently
We know that the photosynthetic organism and the fungus that make up a lichen can exist together on the same surface. Whether or not they can thrive independently, or even survive independently of each other, is beyond the scope of the information we're given.
2%
Correct88% picked this
Serious air pollution in a region can cause problems
Why this is right
We're definitely lichen this answer. We're told that some lichens are very vulnerable to compounds found in polluted air. We're also told that these compounds can damage lichen. This supports the idea that serious air pollution can cause problems for lichens.
Skill tested: Most Supported · how this choice captures the argument's function is the move to repeat next time.
88%

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