Viruses use the cells of living organisms to reproduce. The cell which is used by virus is called as "host cell". It is a living cell in which virus multiplies, example bacteria, plant or an animal cell.
In this, the virus is a parasite, which uses host cell for its benefit (reproduction) by using the cell machinary of host cell.
Homeostasis is an organism ability to maintain equilibrium [which means balancing opposing forces]. When we sweat our body it is trying to stop overheating.
