Answer:
THE ROMAN REPUBLIC 
In many ways, the Roman Republic was very similar to the way in which the United States government is organized today. There are three clear divisions of power, as you will see below. 
 
EXECUTIVE BRANCH 
Consuls: Elected by an assembly; ruled as chief executives for one year; controlled the military 
 
LEGISLATIVE BRANCH 
Senate: Consisted of 300 members; chosen by aristocrats and responsible for foreign affairs and financial policies 
Centuriate Assembly: A group of citizen soldiers that were members for life; elected consuls and drafted/passed legislation 
Tribal Assembly: Citizens put into groups depending on where they lived; members for life; elected tribunes 
 
JUDICIAL BRANCH 
Praetors: Eight judges chosen by the Centuriate Assembly to serve for a year; two of the eight supervised civil court and criminal court 
 
LEGAL CODE 
βThe Twelve Tables was similar to the Bill of Rights (the first ten amendments of the Constitution), but it only protected free-born male citizens under the law. 
 
CITIZENSHIP 
Given to adult man landowners. 
 
ONE MAJOR DIFFERENCE 
Dictators: Appointed by consuls and elected by the Senate in a time of catastrophe; power lasted for six months 
 
THE AMERICAN REPUBLIC 
The Founding Fathers of The United States borrowed some of the elements of government from Rome, yet developed and added quite a few innovations. Unlike Rome, checks and balances came from the workings of three areas of government: a President, who was responsible for the jobs of Commander in Chief of the military, could appoint ambassadors to conduct foreign policy, and could propose laws to the Legislative Branch; the Legislative Branch is bicameral, including both a Senate, whose members are elected for six year terms, and a House of Representatives, whose members are elected for two year terms. Both houses need to agree on a law before it is sent to the President for signature. Finally, they created an independent Judiciary known as the Supreme Court whose job it was to ensure that laws passed by the Legislature were consistent with the U.S. Constitution.