PrepTest 137, Section 2, Question 5
The hormone testosterone protects brain cells from injury(40 more words not shown)
Which one of the following(5 more words not shown)
- Aanyone whose brain(10 more words not shown)
- Bwhether a person(16 more words not shown)
- CAlzheimer's disease leads(6 more words not shown)
- Donly people with(10 more words not shown)
- Ea decline in(10 more words not shown)
Reading the argument
Testosterone appears to help in two ways. Let's connect each benefit to Alzheimer's disease.
First, it reduces beta-amyloid, a protein that contributes to the disease. Reducing something that contributes to a disease gives us a reason to think the hormone could be protective.
Second, testosterone protects brain cells from injury. People whose brain cells are vulnerable to injury are probably more vulnerable to Alzheimer's disease too. That gives us another connection between testosterone's protection and a lower risk of the disease.
What we’re looking for
So I'd finish the argument with the idea that testosterone could help protect against Alzheimer's. We're drawing a supported conclusion, not claiming that one hormone determines everything about whether someone develops the disease.
Working the answers
- A
Greater susceptibility isn't certainty. The passage says people with vulnerable brain cells are probably more susceptible to Alzheimer's disease; A says everyone in that group will eventually get it. A risk can be higher without the outcome being inevitable.
- B
Beta-amyloid contributes to the disease. That doesn't mean its level entirely determines whether someone develops it. There could be genetic, environmental, or other contributing factors. In fact, the passage also gives us a separate reason to consider vulnerability to brain-cell injury. B turns one contributing factor into the whole explanation.
- C
The passage gives us reason to think testosterone affects the risk of Alzheimer's. It doesn't say Alzheimer's lowers testosterone. Evidence about what a hormone does to disease risk isn't evidence about what the disease does to the hormone. C adds a causal claim in the other direction.
- D
Why would someone need Alzheimer's disease to be at risk of brain-cell injury? Think of someone playing football: injury risk doesn't require that disease. More directly, the passage says vulnerability to brain injury may increase disease risk; it never limits injury risk to people who already have Alzheimer's.
- ECorrect
This expresses the protective connection from the other side: if testosterone declines, some of that protection can decline, putting the person at increased risk. Less protection against injury and less reduction of beta-amyloid both make that conclusion reasonable.
The wording is slightly different from my prediction that testosterone could protect against Alzheimer's, but the underlying connection is the same. E describes increased risk, not a guarantee that the person will develop the disease.
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