Is it ensure, insure, or assure?
psychobiology psy·cho·bi·ol·o·gy (sī'kō-bī-ŏl'ə-jē)
The study of the biological foundations of the mind, emotions, and mental processes. Also called biopsychology.
The school of psychiatry that interprets personality, behavior, and mental illness in terms of adaptive responses to biological, social, cultural, and environmental factors.