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

Question

Quizplus · Accepted Answer

Scientists have found evidence that suggests that an asteroid impact was the triggering event for the Cretaceous mass extinction. This is supported by the discovery of a layer of sediment that contains high levels of iridium, which is rare on Earth but common in asteroids. Additionally, the impact crater at Chicxulub, Mexico, is the right age and size to have been the cause of the extinction.

Scientists Evaluating the Cretaceous Mass Extinction Have Concluded That