what is the predominant brain wave activity observed during sleep (nrem)? - delta waves - theta waves…

Brief Explanations:

During non - rapid eye movement (NREM) sleep, especially in deep sleep (stages 3 and 4), delta waves are the dominant brain wave activity. Delta waves have a low frequency (0.5 - 4 Hz) and high amplitude. Theta waves (4 - 8 Hz) are more prominent in lighter NREM sleep (stage 2). Alpha waves (8 - 12 Hz) are associated with a relaxed, awake state with eyes closed. Beta waves (12 - 30 Hz) are present during an alert, awake state.

Answer:

Delta Waves