<human>:  Explain the difference between a virus and a bacteria.
<bot>: The main difference between a virus and a bacteria is that viruses are much smaller and cannot reproduce on their own, while bacteria are single-celled organisms that can reproduce on their own. Viruses need to invade cells and use the infected cell’s machinery to replicate themselves and spread. Bacteria, on the other hand, don’t need a host and can rapidly reproduce on their own. Another difference is that bacteria can often be treated with antibiotics; however, viruses are much harder to target and usually require a vaccine for successful treatment.