Question

NREM sleep normally exhibits how many distinct stages, which appear to alternate?

1) Two
2) Three
3) Four
4) Five

Answer 1

NREM sleep is divided into three stages: stage 1, stage 2, and stage 3. So, the correct answer is Two (option 1).

Step-by-step explanation:

The question is asking about the number of distinct stages in NREM sleep and how they appear to alternate. NREM sleep is divided into three stages, which are stage 1, stage 2, and stage 3.

Stage 1 sleep is a transitional phase between wakefulness and sleep, with a slowdown in respiration and heartbeat. Stage 2 sleep is characterized by the appearance of sleep spindles and K-complexes. Stage 3 sleep, also known as deep sleep or slow-wave sleep, is characterized by low frequency, high amplitude delta waves, and slow heart rate and respiration.

Therefore, the correct answer is Two (option 1).