People who have something in common, and who believe that what they have in common is significant, form a:

social group.

Explanation:

Social groups are defined by the interaction established between people and the existing sense of identity. Systematically and consistently, within a social group, the individuals who compose it develop a stable relationship, since they share common interests.

Thus, members of this type of group share stories, goals, interests, values, principles, symbols, traditions and, above all, the laws and norms that ensure interpersonal relationships and the performance of certain roles between social subjects.

These groups develop much of their reflections from their surroundings to conclude that a social group has a primary role in shaping society. It assists in the creation of a group identity as well as in the formation of tastes and preferences, values and worldviews.

the density would be a smaller number.

it should be d or b but i'm sure it's d