Q. Consider the following statements regarding the human sleep cycle:

1. REM sleep is characterized by rapid eye movements and vivid dreaming.
2. Deep NREM sleep plays a vital role in physical restoration and repair.
3. As humans age, the duration of REM sleep tends to decrease.

Which of the above statements is/are correct?
Answer: 1, 2 and 3
Notes: REM sleep includes rapid eye movements and vivid dreams, while deep NREM sleep is necessary for tissue repair and growth. Studies show REM sleep duration declines with advancing age. Therefore, all statements—1, 2, and 3—are accurate with respect to human sleep physiology.