__________ develop when two eggs each get fertilized by two different sperm, resulting in two zygotes in the uterus at the same time

__________ is the most common excitatory neurotransmitter in the brain

Fill in the blanks with correct word

A child who had been overly frustrated in the oral stage, such as being weaned too early, would develop an adult personality that might include smoking cigarettes, nibbling fingernails, and a tendency to make "biting" remarks

According to Freud this individual has developed a(n) _____. a. fixation b. Oedipal complex c. crisis d. reality principle