PrepTest 145, Section 2, Question 3
The current sharp decline in commercial honeybee populations(60 more words not shown)
Which one of the following(9 more words not shown)
- ACommercial honeybees are(10 more words not shown)
- BThe results of(8 more words not shown)
- CThe genetic diversity(7 more words not shown)
- DIn the past,(10 more words not shown)
- ELack of genetic(9 more words not shown)
Reading the argument
An infection can be the immediate cause of a bee's death while something else makes the bee especially vulnerable to that infection. So the author's suggestion of an underlying problem is possible. It doesn't have to compete with every disease or pesticide already mentioned.
But how have we established that the underlying problem is inbreeding? Deliberately breeding bees isn't, by itself, the same as breeding closely related bees. The passage does give us something more: these practices have limited genetic diversity. We should accept that fact while still asking how well it supports the proposed explanation for the deaths.
What we’re looking for
The question asks for an assumption the argument needs. My first concern is the connection between those breeding practices and the claimed inbreeding problem. We need an unstated step the author depends on, rather than another interesting fact about bees or advice about how to fix the decline.
Working the answers
- A
Commercial and wild bees could be equally vulnerable to the effects of inbreeding. The argument could still work if commercial breeding practices have created the relevant problem in commercial populations. The author doesn't need commercial bees to be inherently more vulnerable than wild bees.
- B
How quickly we can undo the breeding practices' effects doesn't determine whether those effects help explain the current deaths. A problem could be easy to fix and still be a real underlying problem right now.
- C
The loss of diversity needn't still be getting worse. Imagine that diversity dropped substantially and then stayed at that low level. The resulting vulnerability could persist even though diversity had stopped declining. C adds a continuing trend the explanation doesn't require.
- D
We know these threats devastated bees before. We aren't told those earlier populations were genetically diverse, and the author doesn't need them to have been. They might also have had limited diversity. Either way, the question here is whether the present loss of diversity contributes to the present vulnerability.
- ECorrect
This supplies another missing connection: reduced genetic diversity must be capable of making the bees more vulnerable to the harmful conditions. Otherwise, why bring up genetic diversity as part of an explanation for the deaths?
If low diversity couldn't increase vulnerability at all, the breeding history would give us no reason to identify it as an underlying contributor to infections, poisonings, or infestations. E links the fact we are given—limited diversity—to the explanatory role the author wants it to play. We need that link even though my initial question focused on how the breeding practices establish inbreeding.
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