PrepTest 120, Section 3, Question 14
Overexposure to certain wavelengths of strong sunlight is(54 more words not shown)
Which one of the following,(11 more words not shown)
- AThere is no(14 more words not shown)
- BThere are people(11 more words not shown)
- CMany sunblocks need(11 more words not shown)
- DToxins contained in(6 more words not shown)
- ESunburns appear immediately(12 more words not shown)
Reading the argument
Preventing a sunburn is the test. Preventing melanoma is the goal. Do those necessarily go together?
Let's accept the passage's claim that overexposure to certain sunlight wavelengths is the main cause of melanoma. The doctors' recommendation initially sounds sensible: use something that protects your exposed skin. But look at how they decide what counts as adequate. It only has to prevent sunburn, even during a long exposure.
What we’re looking for
What if someone could avoid a burn and still be exposed to whatever causes the cancer? Then passing the doctors' sunburn test wouldn't establish the protection they want. That's my prediction for a weakener: a reason preventing sunburn might fail to prevent melanoma. We need to question the connection between the stated test and the intended result.
Working the answers
- ACorrect
This challenges the evidence for that connection at the wavelength level. We have no evidence, according to A, that the wavelengths causing sunburn are also ones causing melanoma. So why use prevention of sunburn as the test for protection against melanoma?
Imagine two sets of wavelengths, drawn in red and blue. Suppose the sunblock stops the red ones that burn skin, but the blue ones that can cause melanoma still get through. That is an illustration of the possible gap, not something A proves actually happens. “No evidence” of overlap doesn't prove there is no overlap. It does undermine the basis for treating the sunburn test as adequate protection against the stated danger.
- B
Allergic reactions could matter when choosing a particular product. But this doesn't show that the protection against sunburn fails to address melanoma, and it concerns certain chemicals in many products, not every possible preparation. A more directly challenges the reason the doctors give for calling protection adequate. We shouldn't confuse a possible side effect with evidence about this cancer-prevention link.
- C
Reapplying a product can be inconvenient without making it ineffective. The recommendation is to use adequate sunblock; it doesn't promise that one application lasts indefinitely. A need for repeated applications is compatible with the recommended protection working when maintained.
- D
The argument calls sunlight the main cause, not the only cause. A product could protect against harm from sunlight without preventing every other route to melanoma. Also, the answer doesn't say these toxins are ingredients in the sunblock. We can't add that connection.
- E
Different times of appearance don't establish that protection against the two conditions is disconnected. A precaution taken now could help prevent a problem that would otherwise appear years later. The delay alone doesn't challenge the relevant relationship as A does.
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