The body is at its lowest level of functioning during _____ sleep.

• A. REM
• B. N1
• C. N2
• D. N3

Answer: (D)

Verified step by step guidance

1. Understand the stages of sleep: Sleep is divided into two main types: REM (Rapid Eye Movement) and non-REM sleep, which is further divided into stages N1, N2, and N3.
2. Recognize the characteristics of each sleep stage: N1 is the lightest stage of sleep, N2 is a deeper sleep where heart rate slows and body temperature drops, and N3 is the deepest stage of non-REM sleep, also known as slow-wave sleep.
3. Identify the physiological changes during N3 sleep: During N3, the body is at its lowest level of functioning, with the slowest brain waves, reduced heart rate, and minimal muscle activity.
4. Compare the levels of functioning across sleep stages: REM sleep involves increased brain activity and dreaming, while N1 and N2 involve lighter sleep stages with more bodily activity compared to N3.
5. Conclude that N3 is the stage where the body is at its lowest level of functioning, characterized by the deepest sleep and the most significant reduction in physiological activity.