Final answer:
Individuals benefiting each other in a relationship based on needs relates to exchange principles according to social exchange theory, which is about maximizing benefits and minimizing costs in social interactions.
Step-by-step explanation:
The interactions that involve individuals benefiting each other in a relationship based on each other's needs are best described by exchange principles. This concept is related to the social exchange theory, which suggests that humans are motivated to maximize benefits and minimize costs in their social interactions. The various forms of social interactions, such as communitarianism which emphasizes the importance of community and social responsibility, or social exchange which assesses the cost-benefit analysis in relationships, all aim to navigate through these principles of human interaction and societal organization.