The rare element iridium has been implicated in which "ancient health" crisis?
A)poisoning of primitive algae in the Hadean Eon
B)extinction of the woolly mammoths in late Pleistocene time
C)disappearance of Neanderthal man during the early Cenozoic Era
D)extinction of the dinosaurs at the end of the Cretaceous Period

Question

Quizplus · Accepted Answer

The rare element iridium has been found in high concentrations in a layer of sediment dating back to the end of the Cretaceous Period, around 65 million years ago. This layer is associated with the mass extinction of the dinosaurs, and many scientists believe that the iridium was deposited by an asteroid impact which caused global environmental changes leading to the extinction event.

The Rare Element Iridium Has Been Implicated in Which "Ancient