WeakenDiff: Hard

Logic Breakdown

Passage Summary: Since sun exposure causes skin cancer, doctors recommend using sunblock that is strong enough to stop you from getting a sunburn.

Conclusion: People should use adequate sunblock to prevent melanoma.

Reasoning: Sunlight is the primary cause of melanoma, and adequate sunblock is defined as a product that prevents sunburn during long exposure.

Analysis: To weaken this recommendation, we need to drive a wedge between 'preventing sunburn' and 'preventing melanoma.' The argument assumes that if you stop the burn, you stop the cancer. Look for an answer that suggests the specific wavelengths causing melanoma are not blocked by standard 'sunburn-preventing' sunblock, or perhaps that sunblock gives users a false sense of security, leading them to stay in the sun long enough to cause damage despite not burning.

Passage Stimulus

Passage Redacted

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14.

Which one of the following, if true, most weakens the recommendation that people wear adequate sunblock?

Correct Answer
A
A undercuts the recommendation by attacking the proxy: if there is no evidence that the same wavelengths cause both sunburn and melanoma, then a sunblock that merely prevents sunburn (the definition of “adequate”) may not protect against melanoma-causing wavelengths. That makes the recommendation to wear such sunblock less justified as a melanoma-prevention measure.
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