Who were the 3 main groups of early Americans?

Paleo-Indians,indigenous peoples of the Americas and Lithic stage

Explanation:

Paleo-indians were the first peoples who entered, and subsequently inhabited, the Americas during the final glacial episodes of the late Pleistocene period.The indigenous peoples of the Americas are the pre-Columbian peoples of North, Central and South America and their descendants.Lithic stage was the earliest period of human occupation in the Americas, as post-glacial hunters and collectors spread through the Americas

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