Society includes numerous institutions like religion, art, and government. It is still unclear how people and these institutions interact. Among the viewpoints of anthropologists are the following: Functionalists think that the institutions are created only to serve some need of the people. Structural-functionalists think that once the institutions are created, they exist in a complex web of other institutions and serve only to perpetuate themselves; they may cease serving some need of the people. Marx thought that social instutions resulted from conflicts between various classes of people, which come into being once people start doing agriculture. Durkhiem thought that the social instutions, once in place, fostered stagnation and stasis. A single society can include multiple cultures, and will affect how people of different cultures interact with one another.