[Solved] The usual pH of gastric juice is approximately which of the following values? A) 2 B) 4 C) 6 D) 7 Erectile Disorder: This refers to a type of sexual impairment where an individual cannot sustain or achieve penile erection during sexual engagement. Erotic Plasticity: Erotic plasticity refers to the degree to which an individual's sex drive can be changed by societal, situational, and cultural influences. Sexually Transmitted Infection: A sexually transmitted infection (STI) is an infection that is primarily spread through sexual contact. Nocturnal Emission: An involuntary ejaculation of semen that occurs during sleep, also known as a wet dream.