Covid 19 image.   A virus is a submicroscopic agent that replicates only inside the living cells of an organism. Viruses interact with all life forms, from animals and plants to microorganisms, including bacteria and archaea.  Most viruses use endocytosis to enter the host cell.  A key step in covid‐19 pathogenesis is the entry of the SARS‐CoV‐2 virus into the airway epithelial cells. Polymime is a UK based animation company offering royalty free medical stock images and medical stock videos. Other services including 3D rending, medical animation interactive 3D, vfx and more.