For the central Americans ( Aztecs and Mayas):
Agriculture, specially the production of corn amongst other commonly grown plants.
The cultural most important legacies of these two civilizations are their architecture and stone/clay work.
They had a noticeable hierarchy, mostly religion-driven meaning that the I portable of people depended on their relationship with the gods and religion in general.
For South Americans (Incas):
The production of potatoes amongst other commonly grown plants such as corn where an important economical key.
The cultural legacy of the Inca lies in their amazing architectural techniques.
They're political hierarchy was noticeable and was also religion-driven meaning that the I portable of people depended on their relationship with the gods and religion in general.
Hope it helped,
BioTeacher101