This can put their circadian rhythm, or biological clock, in conflict with the school bell, ... The result illustrates a critical trend: too many teens come to school too sleepy to learn. And their fatigue often leads to behavior problems that contribute to a negative overall school performance and experience.  -   Mary Carskadon     Quotes
This can put their circadian rhythm, or biological clock, in conflict with the school bell, ... The result illustrates a critical trend: too many teens come to school too sleepy to learn. And their fatigue often leads to behavior problems that contribute to a negative overall school performance and experience. Mary Carskadon
 Conflict