In the mass extinction 65 million years ago, ______ of all species on earth vanished.

A．a historian
B．aloof
C．humorous
D．an immigrant

A．there is a consensus about the causes of the end-Permian mass extinction
B．man would not have existed without the end-Permian mass extinction
C．insects are more adaptable in coping with natural devastations
D．natural catastrophes must have hindered the evolution of life