Answer:
Athenian democracy developed around the 6th century BC in the Greek city-state (known as a polis) of Athens, comprising the city of Athens and the surrounding territory of Attica. Athenian democracy is often described as the first known democracy in the world. Other Greek cities set up democracies, most following the Athenian model, but none are as well documented as Athens' democracy.
Explanation:
The Mississippi-Missouri-Ohio river system is the largest and most significant river system in the world.
I think the answer is A)Natural Springs
