What was one major reason that early peoples in north america were able to build complex cultures?

As is true with most early civilizations, the early peoples of North America were able to build complex cultures due to the abundance and ability to undertake large-scale agriculture. Peoples such as the Olmecs, Aztecs, and Mayans in Mesoamerica were situated in areas with favorable climates enabling food production, which, in turn, allows for population growth, specialization, large-scale construction, and state formation!

Ibelieve the answer is water and oil.