What term do sleep researchers use to designate Stages 1 to 4 of sleep?

To avoid "choking" while he is putting, a golfer must try to

a. increase his arousal level. b. decrease his arousal level. c. increase his "flow" state through depersonalization. d. focus on previous errors in putting so he won't repeat them.

For the past few months, Val felt completely hopeless and unmotivated. She would not eat much and felt worthless. Then, she suddenly felt unusually elated, full of energy, and bursting with ideas. Val is probably suffering from ____ disorder

a. ?persistent depressive b. ?conversion c. ?bipolar I d. ?major depressive