[Solved] The inferior one-third portion of the uterus that projects into the vagina is the A)isthmus. B)fornix. C)fundus. D)body. E)cervix. Habituation: Decreasing responsiveness with repeated stimulation. As infants gain familiarity with repeated exposure to a stimulus, their interest wanes and they look away sooner. Erotic Stimulus: Any object, situation, or aspect of the environment that induces sexual arousal or desire. Romantic Fantasies: Imaginative thoughts or daydreams focused on idealized romantic ideals or relationships. Sex: In psychology, the biologically influenced characteristics by which people define male and female.