How does a virus infect a host cell? a. it lays its lipids on a host cell. b. it lays its proteins on a host cell. c. it injects its nucleic acids into a host cell. d. it injects its carbohydrates into a host cell. how does a virus infect a host cell? a. it lays its lipids on a host cell. b. it lays its proteins on a host cell. c. it injects its nucleic acids into a host cell. d. it injects its carbohydrates into a host cell.