Ncient Government and its impact on the United States government

Essay Question 3: Greece and Rome established a structured government that has had a profound influence on the founding fathers of the United States. Discuss their government and assess the contribution made by each of those civilizations to the United States governmental system.
This is the exact question pertaining to the essay. The course is a Western Civilization history class and the sources cited need to be credible. There also has to be a bibliography at the end.