In Asia, where palm trees are non-native, the trees' flowers have traditionally been pollinated by hand, which has kept palm...
GMAT Critical Reasoning : (CR) Questions
In Asia, where palm trees are non-native, the trees' flowers have traditionally been pollinated by hand, which has kept palm fruit productivity unnaturally low. When weevils known to be efficient pollinators of palm flowers were introduced into Asia in 1980, palm fruit productivity increased — by up to 50 percent in some areas — but then decreased sharply in 1984.
Which of the following statements, if true, would best explain the 1984 decrease in productivity?
Passage Analysis:
| Text from Passage | Analysis |
| In Asia, where palm trees are non-native, the trees' flowers have traditionally been pollinated by hand, which has kept palm fruit productivity unnaturally low. |
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| When weevils known to be efficient pollinators of palm flowers were introduced into Asia in 1980, palm fruit productivity increased — by up to 50 percent in some areas — but then decreased sharply in 1984. |
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Argument Flow:
The passage presents a chronological problem. We start with low palm productivity due to manual pollination, then see an improvement when weevils were introduced, followed by an unexplained sharp decline in 1984.
Main Conclusion:
There is no explicit conclusion in this passage - it's actually setting up a puzzle that needs explanation through the answer choices.
Logical Structure:
This isn't a traditional argument with premises supporting a conclusion. Instead, it's a fact pattern that establishes a mystery: why did palm productivity drop sharply in 1984 after the weevil solution had been working well? The passage provides the timeline and context needed to evaluate potential explanations.
Prethinking:
Question type:
Paradox - We need to explain why palm fruit productivity decreased sharply in 1984, even though the weevil pollinators had been successfully increasing productivity since 1980.
Precision of Claims
The key claims involve specific timing (1980 introduction, 1984 decrease), specific activity (weevil pollination), and quantified results (up to 50% increase followed by sharp decrease). We must respect these exact facts.
Strategy
For paradox questions, we need to find explanations that resolve the apparent contradiction between the weevils' initial success and their later failure. We should think about what could have changed between the successful period (1981-1983) and 1984 that would specifically affect the weevils' ability to pollinate or survive.
This explains why farmers might have reduced palm production due to economic factors, but it doesn't explain why the trees themselves became less productive. The question asks about productivity decrease, not production decrease due to market forces. Economic factors wouldn't affect the trees' biological ability to produce fruit.
This discusses why imported trees are initially more productive, but it doesn't explain the 1984 decrease. The passage already established that palm trees are non-native in Asia, so this choice addresses the wrong part of the timeline and doesn't resolve the paradox of decreased productivity after initial success.
This perfectly explains the 1984 decrease. The weevils caused rapid productivity increases from 1980-1983, which depleted the trees of essential nutrients over those years. By 1984, this nutrient depletion would manifest as decreased productivity because trees lacked resources for fruit-producing flowers. This creates a logical cause-and-effect chain that resolves the paradox.
If weevil populations remained stable, this would suggest productivity should have remained high, which makes the 1984 decrease even more puzzling rather than explaining it. This choice deepens the paradox instead of resolving it.
This provides background information about pre-1980 pollination but doesn't explain what changed in 1984 to cause the decrease. The weevils were already established and working successfully from 1980-1983, so this historical information doesn't address the timing of the 1984 decline.