Q12 - A lichen is made up of a photosynthetic

[ohthatpatrick]

Question Type:
Inference (most strongly supported)

Stimulus Breakdown:
A lichen is a plant and a fungus living symbiotically on a hard surface. It absorbs minerals from air, from rain, and from the surface its on. Once absorbed, it's never excreted. Some are very vulnerable to toxic compounds, which can come in polluted air and which could damage both the plant and the fungus.

Answer Anticipation:
We're looking for how we could combine any of these ideas. The strongest idea was that "they can't excrete the elements they absorb". You can imagine a causal chain in which polluted air brings toxic compounds to a lichen, which can't excrete them. In general, tough to predict on this one, so I would mainly remind myself to beware overly strong/specific language or out of scope ideas.

Correct Answer:
E

Answer Choice Analysis:
(A) Too strong. It's hard to predict counterfactuals. We know that lichens are vulnerable and can't excrete, but we don't know that those two ar causally connected.

(B) Too strong. Sure, polluted air can hurt them. But that doesn't mean that their existence indicates unpolluted air.

(C) Too strong. There could be tons of reasons why lichens aren't in a region. Even though polluted air could be a reason for few lichens, we wouldn't know from few lichens that there's probably polluted air.

(D) We have no support for independent thriving. We only know about symbiotic living and shared damage from toxic compounds.

(E) YES, this works. This actually does match our vague prediction: polluted air brings toxic compounds that get absorbed by certain lichens, which are very vulnerable to them and can't excrete them

Takeaway/Pattern: Most "most strongly supported" Inference questions test causal relationships. Even just scanning these answers for strength of language would make (E) the early winner: "serious pollution CAN cause problems" is super safe.

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