Questions: During which stage of sleep do brain waves resemble those of waking more than those of quiet sleep? Stage 1 non-REM sleep REM sleep "Delta" sleep Stage 2 non-REM sleep Semiconscious sleep

The answer is the second one: REM sleep.

Explanation for each option:

1. Stage 1 non-REM sleep: This is the lightest stage of non-REM sleep, where brain waves begin to slow down from their daytime wakefulness patterns, but they do not resemble waking brain waves as closely as REM sleep does.

2. REM sleep: During REM (Rapid Eye Movement) sleep, brain waves are very similar to those during wakefulness. This stage is characterized by rapid eye movements, increased brain activity, and vivid dreams. Therefore, REM sleep is the correct answer.

3. "Delta" sleep: Also known as slow-wave sleep or deep sleep, this stage is characterized by delta waves, which are the slowest and highest amplitude brain waves. These do not resemble waking brain waves.

4. Stage 2 non-REM sleep: This stage is deeper than Stage 1 and is characterized by sleep spindles and K-complexes, which are distinct from waking brain waves.

5. Semiconscious sleep: This is not a standard term used in sleep studies, and it does not refer to any specific stage of sleep.

In summary, REM sleep is the stage where brain waves most closely resemble those of waking.