There were 3 branches of government to ensure no branch became too powerful
. These branches were the executive, legislative, and judicial branches. The executive branch was responsible for enforcing laws and was headed by the president. The legislative branch was responsible for making laws and was made up of two houses: the Senate and the House of Representatives. The judicial branch was responsible for interpreting laws and was made up of the Supreme Court and other federal courts. By separating powers between these branches, the framers of the Constitution sought to prevent any one branch from becoming too powerful and abusing its authority.
is that in rome or greece or both
The concept of having three branches of government to ensure a system of checks and balances is not specifically unique to either ancient Rome or Greece. However, the American system of three branches of government was heavily influenced by the ideas of the Enlightenment philosophers and political theorists such as Montesquieu, who believed in the separation of powers to prevent tyranny.
Ancient Greece and Rome did have different systems of government, but they did not have the same three-branch structure that the United States has. In ancient Athens, for example, there was a direct democracy where citizens directly participated in decision-making. In ancient Rome, there was a system of magistrates, assemblies, and a Senate that shared power in varying degrees.
So while the concept of separation of powers and three branches of government has roots in various historical systems, the specific American system we are familiar with today was not directly modeled after the governments of ancient Rome or Greece.