He proposed a transitional period to adulthood called emerging adulthood:

Amber and Jack are very physically attractive. In the U.S. most people would think they are also

a. kind and intelligent. b. unhelpful and ambitious. c. sophisticated and worldly. d. selfish and conceited.

A key stimulus for the release of adenosine from brain cells is

A) low blood insulin levels. B) high levels of triglycerides and glucose in plasma. C) an energy/oxygen deficit in cells. D) consumption of caffeine. E) high levels of insulin.