Logical Reasoning

PT112 · S4 · Q4 A certain gene can be stimulated

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A certain gene can be stimulated by chemicals in cigarette smoke, causing lung cells to metabolize the chemicals in a way that makes the cells cancerous.

Statements

We're mainly reading for Conditional, Causal, Mathematical, or Pivot language. There are some causal words in the first sentence: stimulated by / causing

And there's a Yet pivot, suggesting that the correct answer will sound like a safe synthesis of the Pivot idea with what came before.

We have a little Causal Chain: chemicals ⇢ gene ⇢ lung cells metabolize in cig smoke stimulated chems cancerously

Then we have the pivot saying that smokers that don't have this gene stimulated have just as high a risk of developing lung cancer.

Evaluate

This is a puzzling pivot. If some smokers don't have the gene stimulated, then it won't cause their lung cells to metabolize the cigarette chemicals in a cancerous way. So why would they have as high a risk of lung cancer as other smokers do?

It seems like either the elevated risk of the smokers that do have the stimulated gene is negligible, or it sounds like the smokers who don't have their gene stimulated have some other risk factor for lung cancer that's higher than the smokers who do have their gene stimulated (to balance out and end up at the same overall risk of lung cancer).

Goal

Since this is Must Be True and we thought of more than one way to resolve the confusion, neither one of those explanations must be true. So maybe the answer will just say some weak truth that allows for both sides of the pivot to be true.

4.

If the statements above are true, it can be concluded on the basis of them that

  1. Correct

    stimulation of the gene by

    Why this is right

    This is appealingly weak language (X is not the only factor). Stimulation of the gene causes an elevated risk of lung cancer (causing cells in the lung to become cancerous). If stimulation of the gene were the only factor affecting risk of smokers getting lung cancer, then it would be impossible for people whose gene can't be stimulated to have the same risk. Since we're told that people whose gene doesn't get stimulated have just as high a risk, it means there must be some other thing that can also affect your risk of cancer.

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

    90% picked this

  2. nonsmokers have as high a

    Out of Scope: nonsmokers

    There's no way we can derive a must be true about nonsmokers when we have zero information about nonsmokers.

    4% picked this

  3. smokers in whom the gene

    Contradicted

    The final sentence says that smokers with a stimulated gene have as high a risk of lung cancer as other smokers.

    3% picked this

  4. the gene is more likely

    Out of Scope: Other Chemicals

    We are only told about chemicals in cigarettes stimulating this gene. We have no idea if any other chemicals stimulate the gene.

    2% picked this

  5. smokers are less likely to

    Out of Scope: Don't Have Gene

    We only talked about people who do have the gene, so we can't derive any must be true about people who don't have the gene.

    1% picked this

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