A(n) occurs when a person is physically present but unable to participate in any meaningful way in family interactions, as when a person is in a coma or in late stages of Alzheimer's disease

Before he dies, Juan is checking his insurance, rewriting his will, and making arrangements for his funeral. Juan is dealing with

a. end-of-life issues. b. bereavement c. thanatology. d. grief work.

Ethan watches television frequently, but spends little time on his homework. In an effort to change this, Ethan now is allowed to watch television only after completing his homework. This is an example of

a. the Premack principle. b. negative reinforcement. c. reinforcer sampling. d. behavioral bribery.