One of the strongest lines of evidence of a meteor or comet impact in the late Cretaceous is
A) the extinction of the dinosaurs in only South America.
B) a thin layer of potassium-40 in late Cretaceous fossil strata.
C) a thin layer of iridium-enriched clay in late Cretaceous fossil strata.
D) the warming of Earth's climate in the late Cretaceous.

Question

Quizplus · Accepted Answer

The thin layer of iridium-enriched clay in late Cretaceous fossil strata is one of the strongest lines of evidence for a meteor or comet impact. Iridium is rare in Earth's crust but common in asteroids and comets, indicating that a large extraterrestrial object struck the Earth at that time.

One of the Strongest Lines of Evidence of a Meteor