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Difficulty: MediumStrengthening Arguments

Coastal towns along Gulf Bay recently enacted mandatory nocturnal light-shielding regulations near beach areas to encourage endangered loggerhead sea turtles to nest. Marine biologists observed a 25 percent increase in recorded turtle nests on Gulf Bay beaches in the season following the mandate's implementation. Consequently, conservationists concluded that the light-shielding regulations were directly responsible for the increased nesting activity along Gulf Bay.

Which of the following, if true, most strongly supports the conservationists' conclusion?

  1. Beaches in adjacent regions that experienced identical weather and tidal conditions but did not implement light-shielding regulations saw no increase in loggerhead nesting activity during the same period.Answer
  2. B
    Loggerhead turtle hatchlings, rather than nesting adults, are known to be the group most disorientation-prone when exposed to unfiltered artificial beach lighting.
  3. C
    Several other nocturnal coastal species, including ghost crabs and shorebirds, also demonstrated increased activity on Gulf Bay beaches after the mandate took effect.
  4. D
    Enforcement of the light-shielding ordinance required local municipalities to dedicate significant financial resources and nighttime patrols to achieve compliance.
  5. E
    A severe storm system destroyed several artificial lighting structures along a commercial coastline situated 300 miles away from Gulf Bay during the same nesting season.

Answer

Beaches in adjacent regions that experienced identical weather and tidal conditions but did not implement light-shielding regulations saw no increase in loggerhead nesting activity during the same period.
The correct option provides a control comparison that isolates the light-shielding policy as the cause of the increased nesting. By showing that adjacent beaches sharing identical environmental factors (weather and tides) but lacking the policy did not see any nesting increase, it effectively eliminates alternative environmental explanations.

Step-by-Step Solution

1
Analyze the argument structure.
Premise: Mandatory light-shielding regulations were enacted, followed by a 25% increase in loggerhead turtle nests. Conclusion: Light-shielding regulations directly caused the increase in nesting activity.
Identifying the core causal premise and conclusion is essential before evaluating potential strengthening evidence.
2
Identify logical vulnerabilities in the causal leap.
The argument assumes correlation implies causation and overlooks alternative potential causes, such as favorable weather, tidal changes, or regional turtle population growth.
Causal arguments on the GMAT can be strengthened by ruling out alternative explanations or supplying a control comparison.
3
Evaluate the choices for a strengthening mechanism.
Showing that nearby control beaches with identical environmental conditions but no lighting regulations experienced no change in nesting activity isolates the light regulations as the primary cause.
A control group confirms that the observed effect occurs only when the proposed cause is present.

Key Concept

Strengthening Causal Arguments via Control Comparison
Estimated Time:1m 30s
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Topics

Strengthening Arguments

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