The nervous system is responsible for which of the following? a. removing wastes from the blood b. regulating fluids c. removing toxins from the liver d. controlling reactions to stimuli

I think it's d because that have to control and think

Because without physical activity, the body has extra "energy" if you will, and so when it is time for bed you are not tired, so you end up staying up all night. also there is probably an effect on your internal clock, which messes with your melatonin production which goes hand in hand with your sleep cycle