I believe your answer is the Aztecs.
Answer: A system of supportive federalism emerged, as the authorities of the federal government expanded
Federal government is used to describe the government of the United States as a whole.Federalism is the idea that in the US government power is divided between the government of the US and the government of the individual states. The national government is sometimes called federal government because technically US can be considered a federation of states
Flooding and silt should be the answer
