PrepTest 121, Section 4, Question 12
Some species are called "indicator species" because the(83 more words not shown)
Which one of the following(6 more words not shown)
- AEnvironmentalists sometimes overreact(7 more words not shown)
- BThe loss of(14 more words not shown)
- CEnvironmentalists' use of(11 more words not shown)
- DThe loss of(21 more words not shown)
- EThe loss of(15 more words not shown)
Reading the argument
What if the rabbits disappeared because more foxes arrived?
A falling population might warn us about pollution. But it could also reflect another change in the ecosystem, or something else affecting the animals, such as hunting. The label “indicator species” shouldn't stop us from asking what actually caused this particular decline.
What we’re looking for
That's the caution the author develops. Environmentalists are increasingly using these populations to track pollution, but declines also occur through natural changes. So the author warns against interpreting every loss as environmental degradation. We don't have to abandon the warning sign; we have to avoid treating it as a diagnosis that can have only one explanation. The main-conclusion question asks for that caution about interpretation. The natural-change discussion explains why we should follow it.
Working the answers
- A
“Overreact” suggests that the response is excessive. The author's concern is that the cause of a decline could be misidentified. Someone might react calmly and still wrongly blame pollution. A also claims environmentalists actually sometimes overreact, while the passage warns what would be misguided if they attributed every loss to pollution.
- BCorrect
A lost population shouldn't always be interpreted as environmental degradation. That captures the warning the natural-change evidence supports. The passage itself contrasts declines signaling environmental degradation with declines resulting from the ecosystem's natural evolution, so this wording fits the author's distinction.
- C
Using indicator species isn't itself the problem identified. The problem would be assuming that every population loss has the same explanation. The author allows that declines often provide useful warnings. C broadly calls the practice often problematic instead of stating the specific caution the argument supports.
- D
The first part gives a reason for the author's caution: natural changes can cause population losses. But “should not be resisted” adds a recommendation about what to do when that happens. The author hasn't said that people should leave every natural decline alone. The conclusion concerns how to interpret a loss, not whether to intervene.
- E
The author distinguishes pollution-related declines from natural changes. E instead calls the loss caused by pollution part of nature's normal state. “Change is the status quo” doesn't erase the distinction the argument just made or establish that pollution losses should be treated as ordinary natural change.
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