Young adults (late teens, early 20s) have the lowest rate of sleep disturbances of any age group with the possible exception of babies. They are past the common childhood disorders (night terrors, sleepwalking) but do not yet suffer the insomnia of middle age or the fragmented sleep of old age. This is a generalization, of course, but we can say that young adulthood is the golden age of sleep.
Another contrast with licensure is that, under a licensing law, practitioners of the licensed occupation must have a license in order to practice. It is involuntary. On the other hand, certification is voluntary. One does not have to be certified in order to practice.
0 grams of fat should be the answer if is says fat free