A major chemical spill occurred five years ago at Baker's Beach, the world's sole nesting ground for Merrick sea turtles,...
GMAT Critical Reasoning : (CR) Questions
A major chemical spill occurred five years ago at Baker's Beach, the world's sole nesting ground for Merrick sea turtles, and prevented nearly all the eggs laid that year from hatching. Yet the number of adult female Merricks returning to lay their eggs at Baker's Beach has actually increased somewhat since five years ago. Clearly, environmentalists' prediction that the world's Merrick population would decline as a result of the spill has proven unfounded.
Which of the following, if true, most seriously undermines the argument offered in refutation of the environmentalists' prediction?
Passage Analysis:
| Text from Passage | Analysis |
|---|---|
| A major chemical spill occurred five years ago at Baker's Beach, the world's sole nesting ground for Merrick sea turtles, and prevented nearly all the eggs laid that year from hatching. |
|
| Yet the number of adult female Merricks returning to lay their eggs at Baker's Beach has actually increased somewhat since five years ago. |
|
| Clearly, environmentalists' prediction that the world's Merrick population would decline as a result of the spill has proven unfounded. |
|
Argument Flow:
The argument starts by acknowledging a serious environmental disaster (chemical spill that killed most turtle eggs), then presents seemingly contradictory evidence (more females are nesting now), and concludes that this proves the environmentalists' doom-and-gloom predictions were wrong.
Main Conclusion:
The environmentalists' prediction that the Merrick turtle population would decline because of the chemical spill has been proven wrong.
Logical Structure:
The author uses the increase in nesting females as direct evidence that the turtle population is fine, assuming that more females nesting = healthy overall population. The logic is: if the spill really hurt the population, we shouldn't see more females nesting now.
Prethinking:
Question type:
Weaken - We need to find information that would reduce belief in the conclusion that environmentalists' prediction about population decline was wrong
Precision of Claims
The argument measures 'population health' by counting adult female turtles returning to nest, but doesn't account for timing issues, age of current nesters, or other population factors
Strategy
Look for gaps in the logic that show why counting current adult females doesn't actually prove the spill didn't harm the population. Focus on timing mismatches, alternative explanations for the current count, or flaws in using nesting females as a population measure
This actually strengthens rather than weakens the argument. If the spill occurred when no turtles or eggs were present, then it wouldn't have harmed the turtle population at all, making the environmentalists' prediction even more unfounded. This supports the author's conclusion.
This is the correct answer. It reveals a critical timing flaw in the argument. If female turtles don't start nesting until age 10, then current adult females hatched 10+ years ago - before the 5-year-old spill. The spill's impact on hatchlings won't show up in nesting numbers for another 5+ years. This means counting current nesting females tells us nothing about the spill's actual impact, completely undermining the author's logic.
This doesn't weaken the argument. Whether turtle survival rates are normally high or low doesn't change the fact that we're seeing more females nesting now than before the spill. The author can still point to this increase as evidence against the environmentalists' prediction.
This might actually help explain why more females are nesting (fewer predators eating eggs), but it doesn't undermine the core argument. The author could argue this shows the population is doing even better than the environmentalists predicted, regardless of what's causing the improvement.
This describes a missed opportunity to help the turtle population, but it doesn't weaken the argument about whether the environmentalists' prediction was wrong. The current increase in nesting females still stands as evidence, whether or not additional conservation efforts were attempted.