Viruses use enzymes to destroy host cells after replication is complete.
The human immunodeficiency virus (HIV) is the virus that attacks the cells in the immune system that produce antibodies.
Amoeba
An electron microscope is necessary to actually see a virus.
HIV is passed through unprotected sexual intercourse, dirty needles from tattoos, drugs, etc, and transmission of bodily fluids such as through open cuts or wounds. Hepatitis is passed through dirty needles, certain immunocompromised medications for transplants or cancer, and may also be hereditary.
by blood and body fluids
rusts and smuts
prion
virus
chicken pox
they can fix nitrogen
pathogen