The largest extinction in Earth's history marked the end of the Permian period, some 252 million years ago. A new research finds that the Permian mass extinction in the oceans was caused by global warming that left animals unable to breathe

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The largest extinction in Earth's history marked the end of the Permian period, some 252 million years ago. A new research finds that the Permian mass extinction in the oceans was caused by global warming that left animals unable to breathe