Will vote ! why might most of the major pre-columbian mesoamerican civilizations have existed in the areas of southern mexico?

In southern Mexico the was more places that they could live with everything that they needed because it was such a small area surrounded by water which made farming easier and getting drinking water. Although when it flooded they were forced to rebuild their homes because the flood would have destroyed them. They couldn’t move very far north because they are used to warmer weather and the further north of the equator you are the colder it gets and most of them would die from the cold, not knowing what to do.