Will give brainliest! timed test! vaccinations a. prevent the spread of communicable diseases. b. are only given after the disease has been cured. c. prevent the spread of noncommunicable diseases. d. are used to treat existing disease symptoms.

The answer is a.prevent the spread of communicable diseases

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