The simple question of whether or not viruses are alive, has defied a simple answer because it raises the fundamental issue: What defines life?

Some scientists support the idea that viruses are alive because they contain a nucleic acid.
One key argument against viruses not being alive is that they do not have a cellular structure.
A virus can reproduce asexually via cell division.
Because viruses can spread disease from one organism to another, they are in fact reproducing.
Some scientists believe that a virus responds to its environment when it changes from a dormant to an active form.
Living in a host cell as a parasite qualifies an organism as alive.