Examkin

Question

Difficulty: MediumStrengthen

Ornithologist: Ten years ago, our city implemented a 'Dark Sky' ordinance to reduce nighttime light pollution, which disorients migrating warblers and causes fatal building collisions. Since then, the population of warblers migrating through the city has continued to decline. Critics claim the ordinance failed to protect the birds. However, this is unwarranted. The continued decline is actually caused by the recent, rapid deforestation of the warblers' southern wintering grounds.

Which one of the following, if true, most helps to strengthen the ornithologist's argument?

  1. Populations of bird species that migrate through the city but spend their winters in protected nature reserves have remained stable over the past decade.Answer
  2. B
    The total number of migrating warblers fatally colliding with buildings in the city has increased since the ordinance was enacted.
  3. C
    The primary purpose of the Dark Sky ordinance was to improve conditions for astronomical observation rather than to protect migratory wildlife.
  4. D
    Prior to the implementation of the Dark Sky ordinance, light pollution in the city was known to be the primary cause of warbler mortality.
  5. E
    The rapid deforestation in the southern wintering grounds began at exactly the same time that the city implemented the Dark Sky ordinance.

Answer

The option stating that populations of bird species migrating through the city but wintering in protected reserves have remained stable.
The correct answer acts as a scientific control group. If the Dark Sky ordinance had failed, all birds migrating through the city would still be declining. By establishing that other bird species migrating through the exact same city are stable because they winter in protected areas, it proves two things simultaneously: the city's ordinance successfully eliminated the local threat, and the lack of protected wintering grounds is the true variable causing the warblers' decline.

Step-by-Step Solution

1
Identify the conclusion of the argument.
The ornithologist concludes that the continued decline in the warbler population is caused by southern deforestation, not by a failure of the city's Dark Sky ordinance.
Understanding the precise claim is required to know what needs strengthening.
2
Analyze the evidence and identify the logical gap.
The evidence shows warbler populations are still declining despite the ordinance. The gap is the assumption that the ordinance actually worked and that an entirely different variable (deforestation) is now solely responsible for the decline.
Strengthening often involves closing the gap by validating the assumption or ruling out alternate explanations.
3
Formulate a strengthening strategy.
Look for an answer choice that acts as a control group: a scenario where the birds experience the city's ordinance but do NOT experience the deforestation.
In causal arguments, demonstrating 'cause without effect' or validating a control group effectively isolates the true causal variable.
4
Evaluate the options against the strategy.
The correct answer shows that birds migrating through the city but wintering elsewhere are doing fine, proving the city is safe and the wintering grounds are the problem.
This directly confirms the ornithologist's defense of the ordinance and indictment of the deforestation.

Key Concept

Strengthening Causal Arguments via Control Groups
Rate this question

Topics

Strengthen

More questions from this topic