The dinosaurs first appeared in the Mesozoic and the first mass extinction occurred during the Paleozoic. Moreover, humans first appeared in the Cenozoic.
The dinosaurs emerged during the Triassic Period of the Mesozoic Era, approximately 220-225 million years ago.
The first mass extinction occurred in the Ordovician Period (the second period of the Paleozoic Era).
The Cenozoic is the current geological Era that encompasses the last 60 million years.
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