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

A．old people can easily accept the change
B．people can move from place to place
C．individuals can hardly become innovative
D．economy develops at high speed

A．social agencies in America can be very helpful
B．the help to American families from social agencies is limited
C．the government should do more to improve patchwork programs
D．the fragmentary nature of the American family is unique