What distinguishes the end-Permian mass extinction from other similar devastations

A．the lack of experienced researchers
B．lack of access to southern China
C．lack of relevant rock samples
D．lack of well-preserved fossils

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