which of the following correctly describes the nature/function of sleep? (a) during nrem sleep, the brain is principally concerned with producing innovative insights and problem-solving abilities. 3 (b) nrem sleep strengthens the retention of information that was deemed as important during waking hours, as well as actively removing unnecessary neural connections. (c) compared to nrem sleep, the presence of rem sleep tends to be more heavily concentrated during earlier hours of sleep. (d) in general, rem sleep is more important than nrem sleep because the former helps regulate more advanced cognitive and emotional functions. (e) because the recycle rate of the human brain is 17 hours, the recommended number of hours of sleep is 7 hours for optimal cognitive functioning the next morning.