Rachel has been trying to lose 10 pounds, but she finds herself breaking her diet by eating sweets around 3 p. m. every day. she has low levels of mental alertness and sleepiness around this time of day which is probably due to the universal daily highs and lows in biological and psychological functioning known as:

This is process is known as circadian rhythms. This cycle is an internal clock that tells individuals when to eat or sleep. The night and day cycle plays a important role in this process, because it tells an individual when to perform an action. When it is dark humans usually sleep and when their is light outside humans usually eat. This process can negatively effect a person if they are mentally or physically thrown off their cycle.