They move for better paying jobs
I think it’s A I’m not sure though if I’m wrong I’m sorry .
The Cenozoic spans only about 65 million years, The Cenozoic is sometimes called the Age of Mammals, because the largest land animals have been mammals during that time.
Native Americans were hunter-gatherers, so they saw land as hunting territory, where Europeans saw it as farmland and land to settle on. The native Americans would move around the land to hunt the animals and thus didn't claim land, but the colonist saw it as their land, so it was more important for them.