What is a social group? why are social groups important in society? what are two groups that you are apart of?

A social group is a union of people who are connected by common relationships and have common goals, norms, values, and traditions, as well as united by common activities. The social group also refers in some cases to the unification of people on a significant social basis.  

The group has an influence on personal qualities of the person, character, speech, thinking, interests which, seemingly, are purely individual and have no relation to the social dimension of human existence. The child forms these qualities, communicating with parents, friends, relatives.

Two of my social groups are my family and project.