one-celled organisms without a nucleus

spore-producing organism that feeds on organic matter

an organism that lives in or on another organism (host) and harms the host in some way

a cell that has a nucleus; more complex

a cell that does not have a nucleus; very simple

a living thing or virus that causes disease; commonly called germs

medicines that interfere with the reproduction of bacteria; are not effective against viruses

drugs that can treat people who have already been infected by a virus

can only be used to prevent infections (viral and bacterial) from leading to disease

an organism that carries pathogens from one person or animal to another

the study of microscopic living organisms