Text 1: Paleontologist Owens argues that an asteroid impact alone explains the mass extinction at the end of the Cretaceous period. Iridium-rich layers worldwide, the Chicxulub crater off Mexico's coast, and the abrupt fossil record all point to a single catastrophic event that wiped out non-avian dinosaurs in a geological instant.
Text 2: Paleontologist Voss accepts the asteroid as a major factor but argues that the Deccan Traps — massive volcanic eruptions in India that began before the impact — had already destabilized ecosystems and weakened many species. The asteroid, in this view, delivered the final blow to a world already in decline.
The authors most clearly disagree about
- A
whether dinosaurs went extinct.
- Bcheck_circle
whether the asteroid impact alone explains the extinction.
- C
whether an asteroid struck the Earth.
- D
whether iridium is rare in Earth's crust.
Explanation
Both accept the asteroid impact and the extinction. They disagree on whether the impact alone is sufficient explanation or whether volcanism also played a major role. C captures the dispute.