Final answer:
Option (E), Eighty percent of our sleep occurs across all of the non-REM stages of sleep, including Stage 1, Stage 2, and the deep sleep stages of 3 and 4 combined.
Step-by-step explanation:
The question is asking about the sleep cycle during which the majority of our sleep occurs, which is Stage 2 sleep. According to the information provided, during Stage 2 sleep, sleep spindles and K-complexes emerge, indicating that the body is going into a deeper relaxation phase. Sleep research suggests that we spend about 50% of our sleep time in Stage 2, making it the stage where the largest percentage of our sleep occurs, but not quite 80%.
However, if we accumulate the time spent in all non-REM stages of sleep, which includes Stage 1, Stage 2, and slow-wave sleep (Stages 3 and 4), it may indeed comprise around 80% of our overall sleep time, with the remaining 20% being REM sleep. Therefore, the correct answer addressing the 80% question would be (E) All of the above, if we consider all non-REM stages collectively.