How can this be understood?
Engel based the biopsychosocial model on systems theory.Â
A. A hierarchy of systems in which each system can influence higher and lower systems. These interactions and their emergent properties on a person s health could be considered to be influenced by complexity theory. B. A hierarchy of systems in which each system is simultaneously part of a larger system and contains smaller subsystems. C. A linear cause-effect model that can attribute a single sociological, psychological or biological basis for a given disease. D. Options A and B are true. E. Options A, B and C are true.