Final answer:
The rules that define the familial system's boundaries determine who is considered a family member and the level of participation expected of them.
Step-by-step explanation:
The rules defining who participates in the family and who is considered an outsider, as well as how much participation is expected, define the system's boundaries. Families can be seen as social systems with their own structures and rules that guide interaction among members. Sociologists emphasize the importance of relationships and participation within these units, rather than merely the formal status roles.
The concept of family can vary greatly depending on cultural and sociopolitical contexts, but it generally serves as an economic unit and provides emotional support. Whether through shared household activities or decision-making processes, the way in which families set their boundaries dictates how they function and how members interact both internally and externally.