Scientists evaluating the Cretaceous mass extinction have concluded that
A) an asteroid impact was probably the triggering event for the extinction.
B) climate change would not have been involved in producing the extinctions.
C) ecological factors such as disease and competition probably caused the dinosaurs to go extinct.

Question

Quizplus · Accepted Answer

Scientists have gathered evidence that suggests that an asteroid impact was most likely the triggering event for the Cretaceous mass extinction. This theory is supported by the discovery of a large impact crater in Mexico that dates back to the time of the extinction, as well as high levels of iridium (a rare element found in asteroids) in sediment layers from that time period.

B and C are incorrect. Climate change is thought to have played a role in the extinction, and while ecological factors may have contributed, they are not believed to have been the primary cause of the extinction event.

Scientists Evaluating the Cretaceous Mass Extinction Have Concluded That