[Solved] Before conducting any experiment on humans, a psychological investigator must obtain A) demand characteristics. B) permission from the American Psychological Association. C) a normal distribution. D) informed consent. Saturated Fat: A type of dietary fat found in animal products and some plant oils that is solid at room temperature and associated with increased cholesterol levels. Dietary Supplements: Products taken by mouth that contain a dietary ingredient intended to supplement the diet, such as vitamins, minerals, herbs, or amino acids. Marital Sexuality: The expression, experience, and dynamics of sexual relationships within the context of marriage. Erotic Behavior: Actions or practices that evoke or express sexual desire and excitement.