PrepTest 120, Section 3, Question 19
Although high cholesterol levels have been associated with(76 more words not shown)
Which one of the following(8 more words not shown)
- AIt fails to(8 more words not shown)
- BIt provides no(9 more words not shown)
- CIt presents but(12 more words not shown)
- DIt fails to(17 more words not shown)
- EIt offers no(13 more words not shown)
Reading the argument
What about the cholesterol the argument started with?
The passage gives us an association between high cholesterol and heart disease, then points out exceptions. Those exceptions matter, but they don't erase every possible connection. A factor can contribute to a disease without everyone who has the factor developing the disease, or everyone who develops the disease having that factor.
Then we hear about lipoprotein(a), another blood particle associated with otherwise unexplained heart disease. Dietary changes that affect cholesterol don't affect this particle. Fine. But why conclude that nobody has a heart-related reason to change their diet? A change could leave this one possible risk untouched and still help through cholesterol or another route.
What we’re looking for
For the flaw question, I'd look for that overfocus on one possible cause. The author dismisses all dietary benefit because one possible risk factor doesn't respond to those changes, while setting aside the evidence about cholesterol that could still give some people a reason to make them.
Working the answers
- A
A possible effect of lipoprotein(a) on cholesterol is a different relationship from the one we need to evaluate. Even if that effect exists, we still have to ask whether dietary changes that alter cholesterol could help prevent heart disease. A doesn't identify the author's dismissal of the evidence already presented about cholesterol's possible contribution.
- B
There is evidence of a link: elevated lipoprotein(a) was found in many people whose heart disease wasn't attributable to other causes. That doesn't prove the particle caused their disease; another factor might explain both. But incomplete evidence isn't no evidence. B wrongly treats the stated association as though it were absent.
- CCorrect
The opening association is evidence that cholesterol might contribute to heart disease for some people. The exceptions don't establish that it never contributes. Yet the conclusion dismisses dietary changes that affect cholesterol simply because they don't affect lipoprotein(a).
We don't need to turn the association into proof that cholesterol causes every case. The author is making the sweeping claim that no one has any reason to change their diet for this purpose. Ignoring the possible cholesterol-related benefit leaves that claim unsupported.
- D
Other health problems are outside the conclusion's stated purpose: preventing heart disease. A diet change might have benefits unrelated to the heart, but that wouldn't directly challenge the claim about this particular reason for changing it. C stays with heart disease itself.
- E
The author needn't explain every exception to recognize that a contributing factor might still matter. Perhaps several factors influence who becomes ill. The flaw isn't failure to supply a complete account of those people; it's dismissing a possible benefit to others despite the evidence the passage already provides.
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