Answer:
The main Mesoamerican civilizations are: The Olmecs, who were the oldest mesoamerican civilization, and developed in Southern Mexico, the Aztecs, who ruled over central Mexico, and The Maya, who ruled over the Yucatan Peninsula, Guatemala and Honduras.
The main South American civilizations are: the Chibcha, who inhabited Central Colombia, and the Inca, who inhabited the Andean Cordillera, from the Southermost part of Colombia, to Central Chile.