Though sucking zinc lozenges has been promoted as treatment for the common cold, research has revealed no consistent effect. Recently,...
GMAT Critical Reasoning : (CR) Questions
Though sucking zinc lozenges has been promoted as treatment for the common cold, research has revealed no consistent effect. Recently, however, a zinc gel applied nasally has been shown to greatly reduce the duration of colds. Since the gel contains zinc in the same form and concentration as the lozenges, the greater the effectiveness of the gel must be due to the fact that cold virus tend to concentrate in the nose, not the mouth.
Which of the following, if true, most seriously weakens the argument?
Passage Analysis:
| Text from Passage | Analysis |
| Though sucking zinc lozenges has been promoted as treatment for the common cold, research has revealed no consistent effect. |
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| Recently, however, a zinc gel applied nasally has been shown to greatly reduce the duration of colds. |
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| Since the gel contains zinc in the same form and concentration as the lozenges, the greater effectiveness of the gel must be due to the fact that cold viruses tend to concentrate in the nose, not the mouth. |
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Argument Flow:
The argument starts by showing us a puzzle: zinc lozenges don't work for colds, but zinc nasal gel does work really well. Then it gives us the author's explanation for solving this puzzle - since both treatments have the exact same zinc, the difference must be because cold viruses are mainly in the nose where the gel can reach them, not in the mouth where lozenges would work.
Main Conclusion:
The nasal gel works better than lozenges because cold viruses concentrate in the nose rather than the mouth.
Logical Structure:
The author uses a process of elimination approach: Since we know the zinc content is identical between treatments, the location where the zinc is applied must be the key factor. The argument assumes that viruses being concentrated in the nose explains why nasal application is more effective than oral application.
Prethinking:
Question type:
Weaken - We need to find information that reduces our belief in the author's conclusion that the gel's effectiveness is due to cold viruses concentrating in the nose rather than the mouth
Precision of Claims
The author makes a specific causal claim: since zinc form and concentration are identical between lozenges and gel, the location difference (nose vs mouth) must explain why gel works better. The claim assumes virus location is the key differentiating factor
Strategy
To weaken this argument, we need to find alternative explanations for why the nasal gel works better than lozenges, even though they contain the same zinc. We should look for factors other than virus location that could explain the difference in effectiveness. The author assumes virus location is the only relevant difference, so we need to challenge that assumption
This strengthens rather than weakens the argument. If zinc gel users had both shorter colds AND less severe symptoms compared to non-zinc gel users, this supports the effectiveness of nasal zinc application. This doesn't challenge the author's explanation about virus location - it actually provides additional evidence that nasal zinc treatment works well.
This is irrelevant to the argument's logic. The author isn't making claims about HOW zinc works against viruses - they're explaining WHY nasal application works better than oral application. Whether we understand zinc's mechanism doesn't affect the validity of the location-based explanation.
This seriously weakens the argument by destroying its foundational assumption. The author claims both treatments contain zinc 'in the same form and concentration,' but if lozenges contain citric acid that interferes with zinc's chemical activity, then the zinc isn't functionally equivalent between the two treatments. This provides an alternative explanation for the gel's superior effectiveness - it's not about virus location, but about the zinc in lozenges being chemically compromised.
This doesn't weaken the argument because it applies equally to both treatments. If both lozenges and gel need to be used within 48 hours to be effective, this timing requirement doesn't explain why gel works better than lozenges. The author's location-based explanation remains intact.
This is irrelevant because it doesn't address the comparison between nasal and oral zinc application. Whether nasal spray works as well as nasal gel doesn't challenge the argument that nasal application (gel) works better than oral application (lozenges) due to virus location.