In “Among Teens, Sleep Deprivation an Epidemic,” what do the terms biologically disposed and biologically programmed help the reader understand? that the physical sleep stimulus that causes teens to go to sleep later is controlled by natural conditions but is affected by other factors
that the activities teens are involved in, like sports and part-time jobs, do not adversely affect their genetic tendencies
that the natural accumulation of sleep in teens makes it difficult for them to fall asleep prior to midnight on school nights
that the tendency to become tired in teens is mostly caused by social and cultural factors and not natural conditions