The virus grows in living cells. Viruses are unique in that they cannot reproduce on their own; instead, they must infect a host cell and hijack its machinery to replicate. Once inside a living cell, the virus uses the cell’s resources to produce new viral particles. This process can result in the death or dysfunction of the host cell, and the newly produced viruses can then go on to infect other cells. This is how viruses spread and cause infections. Viruses cannot grow in dead bodies, water, or sugar solutions because they lack the cellular machinery necessary for their replication outside of a living host.