At the End of the Permian Period a Large Mass

Multiple Choice

At the end of the Permian period a large mass extinction occurred; 90-95% of the marine and terrestrial species were eliminated. Which of the following are thought to be the possible cause(s) of this mass extinction?

A) Glaciation.
B) Meteorites colliding with the Earth.
C) Volcanic eruptions.
D) Competition between marine and terrestrial animals.
E) Glaciation or volcanic eruptions.