Why were early people in North America able to build complex cultures? a.
They had learned how to farm.
b.
They had learned how to start fires.
c.
They had advanced weapons.
d.
They had a written language.

1775 is your answer hope this

after the spaniards introduced horses to plains native americans, the lives of the tribes changed. tribes became less settled and sedentary. the horse allowed them to hunt animals such as bison or buffalo, and, instead of staying in one place, tribes began to be nomadic.