Answer:
Polis was the central identity point for the citizens and they revolved around community and religion. This is why most of the art and architecture was developed to support gods and beliefs. Polis always had the temple of the guardian god, as well as other alters to smaller gods they worshiped. Agora was an architectural instance of the community where every social aspect of life was carried out. Depending on the certain identity traits of the poleis, they would develop separately.
Step-by-step explanation:
Greek polis were city-states and their citizens would identify with them. Religion had the central point in the lives of the polis citizens – each had a god or group of gods that they appreciated. The architecture of the polis was therefore subjected to this. There was usually the temple, acropolis, somewhere on the central part of the city and it was developed for the guardian god. There were also often smaller temples and altars around the city for demi-gods, heroes, or other gods (like Hestia, goddess of the home and home fire, that had altered in most of the city-centers).
Some of the cities would build also to fit the religious processions. For example, in Athens, we can still find today the remains of the holy road through which processions would go into the city carrying the sacrifices for the gods. This road was the central road in the polis of Athens where its central gate was positioned.
The community was also very important for the residents, that is why the poleis had agoras – central spaces where people would gather, get the news, do the businesses, and shop. It was the center of the city around which everything devolved.
Because of the possible attacks, most of the polis had walls for protection. They also did not want to be easily attacked and were developed around the coast and the mountains, to lessen the possibility of the attack.
Depending on what was most important to the identity of the poleis, they developed a certain way. Athens, which was very reliable of the trade and was the major economic force in Greece, found the instance of harbor very important. That is how Pireus, the harbor which still exists today, was formed as one of the most crucial parts of the city. On the other hand, Sparta was proud of its military strength and they wanted to prove to all that they are stronger than anyone else. This is why, at one point, Spartan polis did not have walls – they wanted to prove they do not need them and that they can protect the city on their own.