PrepTest 120

Correct. Argument or Facts:
Argument

Valid or Flawed:
Flawed

Question Type:
Weaken

Stimulus Summary:
Background - Overexposure to sunlight is the primary cause of skin cancer
Goal - Prevent
Approach/Recommendation - Apply adequate sunblock
What is adequate? - Anything that prevents sunburn

Answer Anticipation:
This argument has a few factors that we need to pay attention to—the sunlight, the skin cancer, the adequate sunblock, and sunburn. How do they all relate?

Well, the recommendation is to wear adequate sunblock. Since this is meant to prevent skin cancer, the argument is relying on "adequate sunblock" as blocking the overexposure to sunlight that can cause it.

However, adequate sunblock isn't defined as being able to block these wavelengths of sun over a period of exposure. Instead, "adequate" is defined as anything able to prevent sunburn. Sunburn, though, isn't connected to the wavelengths of sunlight that cause cancer! Since the argument assumes a connection between the two but doesn't establish it, the correct answer will likely bring up that distinction—sunburn and skin cancer are caused by different wavelengths of sunlight, and thus preventing sunburn isn't evidence that you've protected yourself against melanoma.

Answer Explanation:
This answer draws a distinction between protecting against the sunlight that causes sunburn and the sunlight that causes melanoma. If there is no evidence that there are wavelengths that cause both, blocking one isn't a sign that you've blocked the other, and thus sunblock that prevents sunburn might not protect against skin cancer. This answer therefore weakens the recommendation in the conclusion.

Key Takeaway:
Understanding the key ideas in an argument and how they relate to each other is key to finding gaps in the logic. Often, identifying all of the key ideas and seeing which ones aren't connected through the premises is enough to know what connection is assumed by the argument.

Incorrect. First, this answer allows for the possibility that there are other sunblocks that wouldn't trigger an allergic reaction. Second, dealing with an allergic reaction is likely not as big an issue as dealing with virulent skin cancer. This answer doesn't speak out against the recommendation in the conclusion.

Incorrect. Since adequate sunblock is defined as preventing sunburn, reapplication as needed is contained within the recommendation if that's needed to prevent it, and thus this answer is considered by the conclusion. Since the argument considers it, it doesn't weaken the argument.

Incorrect. Without tying these chemical compounds to adequate sunblock, this answer is out of scope.

Incorrect. The stimulus establishes that exposure to sunlight causes both sunburn and melanoma. As such, presenting discrepancies in the timeline doesn't weaken the argument since doing so would call into question the causal relationship between the cause and effects, not whether two known effects of a given cause are related to each other.