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Question

Difficulty: MediumAnalyzing Counterarguments and Opposing Viewpoints

Passage:
For decades, conservation biologists asserted that the primary driver of declining kelp forest ecosystems along the Pacific coast was elevated sea surface temperatures resulting from climate shifts. However, recent ecological studies have highlighted the profound impact of sea otter population dynamics on these marine environments. Proponents of the trophic cascade theory argue that sea otters, as keystone predators, regulate sea urchin populations, thereby preventing overgrazing of giant kelp. Skeptics of this ecological model point out that in certain northern coastal bays where otter populations remained robust, kelp beds still experienced severe seasonal die-offs, suggesting that thermal stress remains the decisive factor. Nevertheless, proponents clarify that these localized die-offs occurred exclusively during extreme marine heatwaves that temporarily inhibited kelp nutrient absorption regardless of urchin density. By addressing this apparent anomaly, researchers demonstrated that top-down predator control and bottom-up climatic factors interact rather than act as mutually exclusive forces.

Based on the passage, the author refers to the observation regarding kelp die-offs in bays with robust otter populations primarily in order to:

  1. introduce an opposing perspective to the trophic cascade theory and explain how proponents address this challenge.Answer
  2. B
    present the central claim of the passage that sea otters have no meaningful effect on kelp forest survival.
  3. C
    prove that thermal stress caused by heatwaves is the sole cause of kelp loss across all coastal ecosystems.
  4. D
    provide empirical data showing that sea urchin populations expand rapidly when sea surface temperatures rise.

Answer

The author introduces the observation of kelp die-offs in areas with healthy otter populations as an opposing viewpoint raised by skeptics, then shows how proponents of the trophic cascade theory resolve this counterexample by demonstrating that heatwaves inhibit nutrient absorption independently of urchin grazing.
The correct answer accurately describes the rhetorical function of the passage's reference to kelp die-offs in otter-rich bays. Skeptics use this evidence to challenge the trophic cascade theory, but proponents resolve the challenge by explaining that extreme heatwaves temporarily impair kelp nutrient absorption regardless of sea otter predation. Thus, introducing the objection serves to show how the theory accounts for potential counterexamples.

Step-by-Step Solution

1
Locate the targeted statement in the passage.
The statement appears where skeptics point out that kelp beds suffered die-offs even in bays where otter populations were robust.
Identifying the context reveals who raises the argument and for what purpose.
2
Analyze how the author frames and responds to this statement.
The text presents this detail as a counterexample used by skeptics, followed immediately by proponents clarifying why this anomaly occurred during extreme heatwaves.
Determining the relationship between the counterargument and the author's main synthesis reveals its functional purpose.
3
Evaluate the choices to find the statement that accurately reflects this rhetorical function.
The correct option captures both the introduction of the counterargument and the explanation of how proponents addressed it.
The passage uses this specific case to demonstrate how opposing viewpoints refine the broader understanding of trophic interactions.

Key Concept

Analyzing Counterarguments and Opposing Viewpoints
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Topics

Analyzing Counterarguments and Opposing Viewpoints

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