Researchers examined the or percentage of cases where each twin has a disorder

According to the text, if the young-old slow down their activity level, this is usually due mainly:

a. because they have lost much of their vigor b. because they have little to keep them active c. because of society's expectations that they will do so d. to indicate their unique social status

Mitzi's cat has learned to meow every time it hears the can opener because Mitzi opened the cat food using an electric can opener The cat food now comes in pull-top cans, so the cat never receives food after hearing the can opener. Mitzi's cat stops meowing to the can opener, illustrating that which of the following has taken place?

a. shaping b. extinction c. a spontaneous recovery d. negative reinforcement