One of the most interesting and important advances in neuroscience research was the discovery of the endogenous opioids known as __________

Simultaneous discovery favors which view of history?

a. dynamic? b. ?personalistic c. ?naturalistic d. ?recurrent e. ?syncopated

An ________ is a stimulus that indicates that a particular behavior will be reinforced

a. S? b. S0 c. S– d. SD