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

The white, cheesy coating that protects babies' skin before birth is called

A) endoderm. B) trophoblast. C) organogenesis. D) vernix caseosa.

Which of the following decreases the likelihood that the response will occur again by initiating discomfort?

a. negative reinforcement b. response cost c. positive punishment d. negative punishment