Which of the following mass extinction events is correct?
A. At the end of the Cretaceous period, over 90% of the species went extinct due to a meteorite impacting the Earth's surface and causing a cloud of ash to reduce solar exposure for several weeks.
B. During the Permian period, over 90% of the species disappeared due to an excess of carbon dioxide in the atmosphere.
C. At the end of the Devonian period, 70% of the terrestrial vertebrates went extinct when Gondwana drifted back towards the South Pole.
D. At the end of the Ordovician period, over 90% of the species went extinct due to a meterorite impacting the Earth's surface and causing a cloud of ash to reduce solar exposure for several weeks.
Answer: B
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