HIV-infected T cells help transport the virus throughout the body. ... When HIV is introduced into blood or tissues, the virus binds to CD4 molecules on the surface of helper T cells, injecting its contents into cells and setting off a process that leads to the assembly and release of new virus particles.
Evolution is a process of elimination. the traits that are successful and help them survive are kept for the next population, because they are abet o survive to repopulate. So its improvement.
