<prompt> Delta waves are seen in:Deep sleepREM sleepAwake stateStage II nREM sleep  <response>: REM sleep is characterized by b waves, the waves actually of ale wakefulness. Hence, REM sleep is also called paradoxical sleep. Awake state with eyes closed - a waves; with eyes open - b waves. NREM sleep: stage 1 shows periodic sho bursts of a waves. 