The first condition for the existence of ancient creatures: the absence of a series of devastating disasters. For example, the Great Ice Age, volcanic eruption, large-scale meteorite impact, etc. It's okay for continental plates to move, after all, this process is relatively slow.
Secondly, the earth's ecology must be balanced, so as to meet the conditions for biological survival. Then the number of creatures at the top of the food chain, such as dinosaurs, whether meat-eating or vegetarian, must be greatly reduced. Even its reproductive capacity will be catastrophically weakened.
Of course, the premise of this situation is - a new type of natural enemy. Such as egg thieves, or even more ferocious, larger creatures.
Then, all living things will evolve, and it is impossible to say what evolution will look like. What is essential is that all creatures will live in groups, that is, groups, to form large and small tribes, and even kingdoms will appear. Of course, the owners inside will not be humans.
To know that the emergence of human beings is just a coincidence.
It is necessary that these creatures will eventually master and use technology, and its technology is completely different from what it is today. Because if there is no large earthquake, there will be no energy sources such as coal, oil, and natural gas.
Of course, it is not guaranteed that dinosaurs will become pets of certain creatures, because dinosaurs have lived for more than 160 million years, and in the end they only have the instinct of beasts.
As for the war at that time, it will definitely be very interesting, saying that aliens may not necessarily join in.
After all, everything is hard to say. Maybe the existing technology of mankind has not reached the level of prehistoric civilization!
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