Which best explains why viruses do not have special structures or enzymes that allow them to make the
Viruses can use energy in living cells that they infect.
Viruses can replicate inside a host that they infect
Viruses can cause contagious illnesses in host cells.
Viruses integrate their RNA or DNA into infected cells.

Viruses can replicate inside a host cell that they infect. Viruses are the organisms which have the characteristics of both living and non living things. Virus is non-living outside the cell and present in crystalline form but when a virus is put into a living cell, it starts growing there. When the cell is infected, the virus enters into the another cell and starts infection there.