Viruses can often lead to disease because they -(A)promote the growth of healthy cells.(B)increase the rate of cell division.(C)cause cells to break open and die.(D)remain dormant within the host cell.

"it built up in the atmosphere"

i think thats it, idk, i tried looking for this exact q& a for grad. and idk if i got this question right or sorry if im wrong

answer increasing the intensity, duration,and frequency of exercise progressively;