[Solved] Which of the following is the standard abbreviation for the constraint FOREIGN KEY? A) fkey B) fk C) fky D) frk Reinforcement: Reinforcement is a principle in behavioral psychology that increases the likelihood of a behavior being repeated by applying a consequence or reward. Pornography: Materials (videos, images, writings) depicting sexual content intended to stimulate erotic rather than aesthetic or emotional feelings. Laboratory Noise Blasts: Loud, sudden sounds used in experimental settings, often to study stress responses or auditory processing. Levels of Aggression: Different intensities or types of aggressive behavior, ranging from verbal abuse to physical violence.