Oxygen levels are thought to be lower than present at all times dinosaurs were alive. It went from 12% to 19% in the Triassic. https://phys.org/news/2019-08-dinosaurs-linked-oxygen.html
It stayed in the 11% range throughout the Cretaceous. You must be thinking of when there were giant bugs (Permian? Maybe earlier) when oxygen levels were higher.
But all throughout this era, Co2 levels were way higher than today. This produces more plant growth, which produces more dinosaurs. They could survive today if they get enough to eat and don't die of diseases.
Oxygen levels are thought to be lower than present at all times dinosaurs were alive. It went from 12% to 19% in the Triassic.
https://phys.org/news/2019-08-dinosaurs-linked-oxygen.html
It stayed in the 11% range throughout the Cretaceous. You must be thinking of when there were giant bugs (Permian? Maybe earlier) when oxygen levels were higher.
But all throughout this era, Co2 levels were way higher than today. This produces more plant growth, which produces more dinosaurs. They could survive today if they get enough to eat and don't die of diseases.
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