The thick, greasy substance that covers the fetus around five to six months after conception is called

a. placenta

From an evolutionary point of view, the main advantage of teenage risk taking is that it:

a) causes parents to disengage emotionally from their children. b) pushes young people to venture into the world and experience life. c) helps our species weed out young people who are not fit to reproduce. d) permits society to target which young people are likely to be "bad."

If the instructor walks in the class the day after the CR has been extinguished and

raps on the overhead, the startle response may reappear. This would be an example of (a) spontaneous recovery (b) reverse extinction (c) generalization (d) discrimination (e) negative extinction