[Solved] The structure of stratification is external to individuals. Hypothalamus: A region of the brain that controls bodily functions such as hunger, thirst, sleep, and the release of hormones from the pituitary gland. Sexual Arousal: The physiological and emotional response of the human body to sexual stimuli, which includes physical and psychological changes. Bisexual Attraction: A sexual orientation characterized by the ability to experience sexual, emotional, or romantic attraction to people of both one's own and other genders. Erotic Plasticity: The degree to which an individual's sex drive and erotic responses can be shaped by cultural, social, and situational factors.