Since a virus needs a host to replicate , such as us . Animals etc. It replaces the hosts Cells RNA with its own RNA . Then how does a virus , any virus , form in the first place ? Since it needs a Host to replicate . Is a virus formed within the bacterial its self ? What is the essence of the existence of " Virus " ? What is the " Virus " evolutionary tree ? What is the begining of a virus , what constitutes that primate biological virus form .