Explain the basic principles involved with viral evolution using HIV-1 as your model. Frame your answer in terms of the basic model of how natural...

Explain the basic principles involved with viral evolution using HIV-1 as your model. Frame your answer in terms of the basic model of how natural selection works. Be sure to include in your discussion how viral variation is generated, how the virus manages to evade the immune system, why it is so hard to treat the virus with drugs, and why it has been so difficult to prevent viral infection with a vaccine.