Families preserve a state of equilibrium
Families are by design forces that preserve the status quo.
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The family exists as a sub-system in the much larger societal system.
A family is the oldest and most resilient institution known to humankind. Families are the basic, foundational social units in all human communities are the world, and healthy individuals within healthy families are at the core of a healthy society. Inheritance is a large part of a family system as it allows for familial ties to pass on. It functions on an economic level if wealth is available as well as on a material level if a house, car, or any other material is available for inheritance. Sociologists and anthropologists use two concepts about family: structure and function. The structure refers to the number of family members and familial positions such as mother, father, son, daughter, grandmother, etc. The function refers to how the family satisfies each other in maintaining their domestic structure, such as providing sustenance, building a home as a family, emotionally and physically supporting each other. 
One must have to maintain a healthy relationship with all members of the family to preserve a state of equilibrium. Unhealthy or dysfunctional relationships can create terrible problems that may persist from one generation to the next. Unhealthy relationships may also affect inheritance and how family wealth might be distributed amongst the members, leading to animosity and jealousy between siblings, parents, etc.
[P1] Inheritance is a sociological function of a family unit. [P2] Inheritance allows parents to pass their material wealth to other members of the family. [P3] This increases the likelihood that the family will retain its social and material standing in society. [P4] Therefore, the family is a force that preserves the status quo.