The model that focuses on the multiplicity of influences on health-related behavior (or the focus on complex interactions between individuals and their environment) is referred to as:

Ecological Model.

Explanation:

The Ecological model underlies the multiplicity of the various levels of influences on health-related behaviors, which can be:

Intrapersonal factors: These are the personal factors that influence the individual's behavior, such as personality, beliefs and knowledge.

Interpersonal factors: Correspond to interaction with other individuals, who are responsible for creating barriers or supporting the development of healthy behavior and interpersonal growth.

Institutional and organizational factors: Policies, rules, formal and informal structures that may or may not promote healthy behaviors.

Community factors: Existence of social norms between groups, individuals or organizations responsible for improving or limiting healthy behaviors.

Public policy factors: These are the policies and laws responsible for regulating health practices for disease prevention.