What were the three most important ways that the greeks and romans influenced western civilization? why?

Here's 8 reasons (I couldn't pick which at of all was most important you can do that

1. Democracy
Perhaps the most obvious answer is democracy, which is known to have originated in ancient Athens. However, ancient athenian democracy was an example of a direct democracy unlike modern democracy which relies on delegates. Cleisthenes introduced a series of political reforms which he called Demokratia. Other greek poleis would adopt this system of Athenian democracy.

2. Medicine
The work of Hippocrates had a major influence on the development of western medicine with modern doctors still reciting the hippocratic oath.

3. Drama
The two main Greek forms of drama: comedy (including satyrs) and tragedy have translated significantly into modern theatre genres. Themes of vengeance and murder were notably common in ancient theatre. modern theatre design is also similar to ancient amphitheaters.

4. Architecture
Much of modern architecture is similar to the techniques used in Ancient Greece such as “the golden ratio”. Modern buildings which exhibit some form of order commonly use the same distinctive greek columns and other architectural features.

5. Philosophy and Academia
The most prominent figure of philosophy in Athens was Socrates, despite never writing a single text. Socrates was esteemed by the Oracle of Apollo as being the wisest man in Athens. His student, Plato documented the wisdom of socrates in a series of manuscripts which exhibit advanced logical methods and challenge many of society’s common misconceptions. The socratic method is still used in modern universities and the Platonic academy laid the foundations of western thought. Figures such as Pythagoras and Aristotle also made vital contributions to the modern academia.

8. Religion
Although the polytheistic, complex characterisation of Ancient Greek gods, some aspects of this intertwined mythology and religion has translated into modern society. For instance, it could be argued that the figure of Hades was adapted to the Christian Satan. Many mythological stories have been adopted by popular culture.