In single-subject research, a group of observations of the same individual under the same conditions is known as a ____

Chemical substances in the nervous system that are similar in structure and in action to opiates—such as heroin and morphine—are ________

a. hormones. b. endorphins. c. androgens. d. neurotransmitters.

According to information presented in the text, what is the best indication of when a child has reached the point of optimal readiness?

a. when the child has acquired gross motor skills needed for the task b. when the child develops extrinsic motivation c. when the child begins to imitate simple skills involved in the task d. when the child demonstrates functional subordination of the skills involved