Answer: In a group of city-states, each city-state is independent and rules by its own king. No central power controlled all of the city-states. In an empire, consisting of a nation and the city-states and nations it has conquered, one ruler is in control.
Explanation: One has a king in where the other has just a ruler
After the defeat of Japan in World War II, the United States led the Allies in the occupation and rehabilitation of the Japanese state. Between 1945 and 1952, the U.S. occupying forces, led by General Douglas A. MacArthur, enacted widespread military, political, economic, and social reforms.