What keeps one branch of the federal government from becoming too powerful?

the system of checks and balances
the Bill of Rights in the Constitution
the system of due process of law
the preamble of the Constitution

A Roman censor was responsible for maintaining the census, supervising public morality, and overseeing certain aspects of the government's finances. A Roman tribune was an officer of the Roman army who ranked below the legate and above the centurion. Tribunes had the ability to probit and forbid by making new laws.