_____ are a means by which the family system maintains its equilibrium.​

A) ​Rules
B) ​Goals
C) ​Cognitions
D) ​Expectations

Rules are a set of expectations that are enforced in a family to bring order and stability. These rules maintain the equilibrium of the family system by providing structure, defining roles, and regulating behavior. They also help to establish boundaries and enforce consequences, both of which contribute to the family's overall sense of balance and stability. Goals, cognitions, and expectations can all contribute to the family's overall functioning, but rules are the most direct means by which the family maintains its equilibrium.