Dinosaurs appeared about 200 million to 300 million years ago. Dinosaurs lived on the earth for nearly 6,543.8 billion years. 80 million years ago, an asteroid hit the earth, causing great changes in the earth's environment. The atmosphere is filled with dust, plants die without sunshine for a long time, then lipstick doesn't have enough food, and eventually they all die. This is an inferred result. Asteroids hit the earth. It is said that there is no absolute evidence to prove that it is right at present, but it is very likely. Even if this possibility were true, dinosaurs would not survive today if the asteroid had not hit the earth at that time.
Dinosaurs are very big, much bigger than any living thing on the earth now. Now we know that elephants are big, but they are still much worse than giant Tyrannosaurus Rex pterosaurs. They are worse than these big animals. They also need to breathe like mammals like humans. It also needs oxygen. Otherwise, how can it digest food and do physical activities? 300 million years ago, the oxygen concentration was almost twice as high as it is now, so animals and plants were very big at that time, but now the oxygen concentration has dropped below 20%, and dinosaurs will gradually disappear even if they are not destroyed by that extinction.
Every generation has a time limit. The earth is a big platform. The appearance and disappearance of each generation of creatures are doomed, because every once in a while, large-scale extinction will occur on the earth. As for whether this is caused by completely natural factors or some unexpected factors, no one knows, but five mass extinctions before human beings have proved that no generation of creatures can exist forever, which is nothing more than the length of time.