Answer:
Consuls: the Monarchical Branch
Two magistrates called consuls carried on the functions of the former kings, holding supreme civil and military authority in Republican Rome. However, unlike the kings, the office of consul lasted for only one year. At the end of their year in office, the ex-consuls became senators for life, unless ousted by the censors.
Powers of the Consuls:
- Consuls held imperium and had the right to 12 lictores (bodyguards) each.
- Each consul could veto the other.
- Represented Rome in foreign affairs.
- Consuls presided over the assembly known as comitia centuriata.
Senate: the Aristocratic Branch
Senate (senatus = council of elders, related to the word "senior") was the advisory branch of the Roman government, early on composed of about 300 citizens who served for life. They were chosen by the kings, at first, then by the consuls, and by the end of the 4th century, by the censors. The ranks of the Senate, drawn from ex-consuls and other officers. Property requirements changed with the era. At first, senators were only patricians but in time plebeians joined their ranks.
Assembly: the Democratic Branch
The Assembly of Centuries (comitia centuriata), which was composed of all members of the army, elected consuls annually. The Assembly of Tribes (comitia tributa), composed of all citizens, approved or rejected laws and decided issues of war and peace.