Answer:
Early humans most likely experienced changes in climate forcing migration to find animals for food, changes in climate alternating rivers with droughts and floods and changes in environment causing animal habits changes.
Explanation:
All the changes that early humans could have experienced, I think, are related to the changes that animals and the lands could have suffered. They lived much more closer to them than we do now; now we sometimes don't realize how global warming is affecting our planet because we are not that close to the lands and the crops and we don't usually raise animals for our consumption, we just buy at the shop. But, early humans could sense every change related with that because this was the way they lived. So, migration to find animals, changes in climate alternating rivers with droughts and floods and changes in animal habits are the ones I believe they could have suffered.
