The mesoamerican mexican preclassic period is

The preclassic period covers approximately from 2500 a. C., probable date of the elaboration mainly of the first Mesoamerican pottery; until 200 d. C., in which the fall of Cuicuilco was consummated and the flowering of Teotihuacan takes place. Throughout this period there is a process of evolution acting from egalitarian agricultural societies towards more stratified ones that will conclude with the formation of the Teotihuacan national State.

there are two main types of historical sources: primary sources and secondary sources. a primary source is something that originates from the past. it can be a chronicle, a piece of pottery, or even a piece of glacial ice that gives us climate data about the levels of atmospheric carbon one thousand years ago.

the answer is richard nixion