PrepTest 112, Section 4, Question 4
A certain gene can be stimulated by chemicals(42 more words not shown)
If the statements above are(11 more words not shown)
- Astimulation of the(20 more words not shown)
- Bnonsmokers have as(18 more words not shown)
- Csmokers in whom(16 more words not shown)
- Dthe gene is(14 more words not shown)
- Esmokers are less(12 more words not shown)
Reading the argument
If this gene can make lung cells cancerous, why isn't the risk lower when the gene isn't stimulated? My first reaction is that another route might be involved. Perhaps a different gene or some other process also contributes. Those are possibilities, not mechanisms the passage has identified.
Keep the description precise. The second group doesn't necessarily lack the gene. We are told only that it hasn't been stimulated. Those smokers nevertheless face as high a risk of lung cancer from smoking as other smokers do. So we can't turn the first sentence into a complete explanation of who is at risk.
What we’re looking for
The question asks what follows from the two statements. We don't have to solve the medical mystery. My starting point is simply that smokers remain at risk even without this stimulation. Let's look for an answer that respects that fact without inventing the particular cause.
Working the answers
- ACorrect
Stimulation of this gene cannot be the only factor affecting the risk. If that were the whole account, why would smokers without the stimulation still face just as much risk? Their risk shows that something beyond this one process matters.
This doesn't deny the mechanism in the first sentence. The gene can contribute to cancer while other factors also contribute. A allows both facts to stand and doesn't pretend we have identified what those other factors are.
- B
Both groups in the passage are smokers. The comparison is between smokers whose gene has been stimulated and other smokers, not between smokers and nonsmokers. We have no basis here for assigning nonsmokers the same risk as either group.
- C
This conflicts with the stated comparison. Smokers without the gene's stimulation have as high a risk as the other smokers. C instead makes the stimulated group more likely to develop cancer. The mechanism in the first sentence doesn't license us to disregard the risk comparison in the second.
- D
Cigarette chemicals can stimulate the gene, but the passage doesn't compare their effect with that of other chemicals. Other chemicals might stimulate it more readily, less readily, or equally readily. Knowing that one thing can happen gives us no ranking of its likelihood against alternatives.
- E
Having no gene isn't the same as having a gene that hasn't been stimulated. The passage compares stimulation, not the presence or absence of the gene itself. We therefore cannot conclude that lacking it lowers a smoker's risk. E introduces a different comparison from the one supplied.
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