Answer:
The key difference between American democracy and ancient Greek democracy highlighted in this passage is "Indirect democracy vs. direct democracy."
Step-by-step explanation:
In ancient Greek democracy, particularly in Athens, citizens participated directly in decision-making through an assembly where they could vote on laws and policies. This is an example of direct democracy.
On the other hand, the U.S. Constitution establishes a system of representative democracy, where citizens elect representatives (in this case, Electors) who, in turn, make decisions on their behalf. The passage illustrates the indirect nature of the American democratic process, making the correct answer "Indirect democracy vs. direct democracy."