Mass Extinctions

Multiple Choice

Mass extinctions

A) remove many species,but they are usually replaced within a million years or less by an even greater diversity of life.
B) are caused by human activity and did not occur prior to the expansion of the Earth's human population.
C) remove well- adapted species and groups from the Earth,so that it may take millions of years for species diversity to recover.
D) mainly serve to "weed out" poorly adapted organisms and make room for new,better adapted species.