What principle of government did the authors of the us constitution use to prevent legislative, executive, and judicial power from falling into the hands of a single group?

The principal that is embodies in the United States Constitution to maintain a separation of powers is a system of checks and balances. It divides the central government of the United States into three separate branches that creates a system of checks and balances. Each branch is responsible for their area, legislative, executive and judicial, this allows the branches to check the power of the other branches to makes sure none becomes too powerful.

The answer is athens and sparta.