I think they changed their mind because they discovered the remains of a city-based culture in Mexicos lowlands
They were people in Mesoamerica
The hunter-gatherers of the Nahua people began to move into Mesoamerica in the 6th century. It is believed this was to gain lands and spread political values. As the civilizations mixed, religious and cultural ideas were adopted.
Because they find well imformation that is very ancient
I believe that the type of work you are referring to - excavating historic sites to find evidence to suggest certain things about the lives of ancient civilizations - is done by a mixture of archaeologists, geographers, and historians.
Since population was not counted in ancient time historians can only guess. There are several factors involved. People didn't write at first, nor keep records. The first census was done in 1086, the Doomsday book,when William counted the people of England, the livestock, and broke it down further.
Ancient historians wrote about it.
Ancient Rome is studied by historians and archaeologists who specialise in ancient Rome and people who study the classics.
Anasazi
It allows them to see what has happened in the ancient past. Hieroglyphs is eygyption writing written by very ancient people and if Historians can master sucha a language, they can observe and read about the ancient Eygyptions.
the culture of the people of Mesoamerica had the same type of cities and they also worshiped the same things.
They were people in Mesoamerica
The people of Ashan were descendants of the Hebrews/Israelites. Historians find that the modern day Ashanti of Ghana are the offspring from this ancient people.
An anthropologist or archaeologist
Mesoamerica is like Egypt because they believed in the afterlife and they mummified their people. They also built pyramids.
Mesoamerica
Drinking water
Drinking water