Understanding people as biopsychosocial systems means:

biological factors have the most influence on people, followed by psychological factors and finally social factors.

the nervous system is equal parts biological, psychological, and sociological.

to understand people, we must study how biological, psychological, and social-cultural systems work and interact.

the nervous system is a less important understanding of people that was believed a decade ago.

psychology is the central component in the understanding of human behavior.