Athens was the great Greek cultural center but what modern day nation was a key region of Greek civilization

Italy

Explanation:

Greece is a known which has a rich cultural heritage and is known for its abundant culture and gods. The Greeks however settled in some parts of Southern Italy most notably Sicily. They were responsible in colonizing Italy and helped develop the place through human and mental resources. Some Italians are known to have ancestral Greek ties.This makes Italy the modern country which is a key region of Greek civilization.

it affected it because the kingdoms (with trade) slowly got richer and richer.

mprove the economic conditions for farmers