What are the differences between viruses and bacteria?
Bacteria can survive by themselves, but viruses cannot survive by themselves and need hosts to keep living. Bacteria are single cells that have structures (called organelles) to maintain their life systems. Therefore, they can multiply by themselves and flourish. On the other hand, viruses don't have structures to maintain their life systems by themselves, and they use the structure in host cells. In short, bacteria can keep metabolism, but viruses cannot.