Final answer:
Someone interested in the relationships between behavior and the body works in the field of biopsychology, which studies how the structure and function of the nervous system generate behavior.
Step-by-step explanation:
Someone who is interested in the relationships between behavior and the body works in the field of biopsychology. Biopsychology is a branch of biology that studies how the structure and function of the nervous system generate behavior. It combines aspects of psychology and physiology to understand the biological basis of behavior.