Answer:
Though everyone in ancient Greece spoke the same language  and worshipped the same deities, Greece was not a united country.  Instead Greece was split into hundreds city-states of  which were  small countries that included a city and the surrounding farmland
. The Greek word for a city-state is a polis. A typical  polis had a marketplace called an  and a fortress on a high  hill called an  acropolis. 
Each city-state had its own form of government and system  of laws Athens, for example, is known for its democratic  government where all citizens vote to choose new leaders or  make new laws. Sparta, on the other hand, was ruled by an  oligarchy, which consisted of two kings and a council of important  citizens
. 
Each polis had very different beliefs.  Spartans believed in a strong military  and were trained to be soldiers. In contrast,  Athenians loved the  arts. Athens  produced many great  artists and  writers.
Explanation:
Most terms are explained by the paragraph itself.
Deities is the same as gods/goddesses.
Acropolis literally translates into high-city, like a hill.
A democracy is the form of government where people vote for leaders.
An oligarchy is the form of government where a small group of people who rule a state.