Final answer:
An adult enters approximately four to five cycles of sleep during a full night's sleep, which consist of different stages of sleep including non-rapid eye movement (NREM) sleep and rapid eye movement (REM) sleep. It is recommended for adults to aim for 7-8 hours of sleep each night. The correct option is E.
Step-by-step explanation:
An adult enters approximately four to five cycles of sleep during a full night's sleep. These cycles consist of different stages of sleep, including non-rapid eye movement (NREM) sleep and rapid eye movement (REM) sleep. Each cycle typically lasts about 90-110 minutes and includes multiple stages of NREM and REM sleep.
During NREM sleep, the brain waves slow down and the body relaxes. This is divided into three stages: N1, N2, and N3. N1 is a light stage of sleep, N2 is a transitional stage, and N3 is deep sleep. REM sleep, on the other hand, is characterized by rapid eye movements, vivid dreams, and paralyzed muscles.
Overall, it is important for adults to aim for 7-8 hours of sleep each night in order to complete multiple cycles of sleep and experience the benefits of both NREM and REM sleep. The correct option is E.