Examkin

Question

Difficulty: MediumAnalyzing Divergent Ideas and Disagreement

Passage A
For decades, the prevailing explanation for the Cretaceous-Paleogene (K-Pg) mass extinction has centered on the Chicxulub asteroid impact. The physical evidence is formidable: a global layer of iridium-rich clay, shocked quartz, and a massive impact crater in the Yucatán Peninsula. The immediate consequence of this collision was a catastrophic "impact winter"—a dense shroud of dust and sulfur aerosols that blocked sunlight for years, halting photosynthesis and collapsing food webs globally. This sudden environmental shock explains the rapid disappearance of approximately 75 percent of all species, including non-avian dinosaurs, making the asteroid the definitive catalyst of the extinction event.

Passage B
While the Chicxulub impact is a dramatic historical marker, it was likely a secondary contributor to an extinction process already in motion. Long before the asteroid struck, massive volcanic eruptions in India's Deccan Traps were releasing trillions of tons of carbon dioxide and sulfur dioxide. This sustained outgassing caused severe, multi-millennial global warming episodes followed by rapid cooling, severely stressing Late Cretaceous ecosystems. Fossil records reveal that species diversity was already in steep decline prior to the impact. The asteroid did not initiate the ecological collapse; rather, it struck a biosphere already pushed to its absolute limits by long-term volcanic climate disruption.

Based on the passages, the authors of Passage A and Passage B disagree most strongly about which of the following aspects of the Chicxulub asteroid impact?

  1. Whether the impact was the primary driver of the mass extinction or an incidental event that affected an already failing ecosystem.Answer
  2. B
    Whether physical proof exists to substantiate that an asteroid collision occurred at the end of the Cretaceous period.
  3. C
    Whether the impact caused a multi-millennial period of global warming prior to the volcanic outgassing.
  4. D
    Whether the volcanic eruptions occurred before or after the asteroid collided with the Earth.

Answer

The authors disagree on whether the asteroid impact was the primary driver of the mass extinction or a secondary event that occurred after a volcanically induced collapse was already underway.
The correct answer is correct because Passage A frames the asteroid impact as the central, definitive catalyst for the K-Pg extinction, while Passage B argues that the impact was merely a secondary contributor to a process of ecological collapse that had already been set in motion by Deccan Traps volcanism.

Step-by-Step Solution

1
Analyze Passage A's main claim regarding the asteroid impact.
Passage A claims the Chicxulub impact was the 'definitive catalyst' that caused the K-Pg extinction through an immediate impact winter.
This establishes the first author's perspective on the role of the impact.
2
Analyze Passage B's main claim regarding the asteroid impact.
Passage B asserts the impact was a 'secondary contributor' to a decline already initiated by long-term volcanism.
This establishes the second author's contrasting perspective.
3
Compare the two perspectives to determine the core point of disagreement.
The core disagreement is whether the impact was the primary cause of the extinction or a secondary factor affecting a pre-stressed ecosystem.
Synthesizing the two positions reveals the point of divergence.

Key Concept

Analyzing divergent viewpoints and points of disagreement in comparative science texts.
Estimated Time:1m 30s
Rate this question

Topics

Analyzing Divergent Ideas and Disagreement

More questions from this topic