Answer:
The change of existing human infections and creature infections. Infections recently restricted to little, secluded populaces that would now be able to spread because of mechanical or social changes, for example, the improvement of moderate worldwide travel.
#1 would be A, #2 would be false, as narcotics are incredibly addictive. #3 is absolutely true, as abuse of almost any medical thing can be life threatening.
If the level is moderate. that's the answer.
Cell growth in a disease process kills many of the cells that are just born