[Solved] Marginal cost: A) is calculated as change in total cost divided by change in total output. B) is calculated as change in total output divided by change in total cost. C) increases then decreases, as output increases, to reflect marginal product. D) None of these is true. Sexual Response Cycle: The series of psychological and physiological responses that comprise sexual arousal and activity, including stages such as excitement, plateau, orgasm, and resolution. Sexual Tension: Feelings of erotic desire or attraction toward another person, often accompanied by discomfort or unease due to unfulfilled desire. Genital Secretions: Fluids produced by the genital organs, which can play roles in reproduction, sexual attraction, and disease transmission. Sex Partners: Sex partners are individuals who engage in sexual activity with one another, ranging from a single encounter to a long-term relationship.