Which of the following best describes sleep?

• A. A period of complete unconsciousness with no brain activity
• B. A form of meditation practiced during nighttime
• C. A state in which the body is completely inactive and unresponsive to all stimuli
• D. A naturally recurring state of altered consciousness characterized by reduced sensory activity and voluntary muscle movement

Answer: (D)

Verified step by step guidance

1. Understand that sleep is a complex biological state, not simply the absence of consciousness or brain activity.
2. Recognize that sleep involves altered consciousness, meaning awareness and responsiveness are reduced but not completely absent.
3. Note that during sleep, sensory activity and voluntary muscle movement are decreased, but the body is not entirely inactive or unresponsive.
4. Distinguish sleep from other states such as complete unconsciousness, meditation, or total inactivity by focusing on its naturally recurring and altered consciousness characteristics.
5. Conclude that the best description of sleep is a naturally recurring state of altered consciousness characterized by reduced sensory activity and voluntary muscle movement.