The phrase "brought on" (Line 1, Para 4. ) most probably means _________.

A．90% of animals and plants went extinct 250 million years ago
B．dinosaurs died off as a result of meteor impacts
C．the "Great Dying" has much to do with volcanic activity
D．global warming played a minor part in the "Great Dying"

A．have lost their prominent position in the research community
B．will still play their due role in publishing research papers
C．will fail to keep scientific knowledge up-to-date
D．will become obsolete with the development of "scholarly skywriting"