* Microbe: This is a general term for any microscopic organism. This includes:
* Bacteria: Single-celled prokaryotes (lacking a nucleus).
* Viruses: Not technically living, but rather genetic material encased in protein.
* Fungi: Can be single-celled (yeasts) or multicellular (molds).
* Protozoa: Single-celled eukaryotes (with a nucleus).
* Microscopic algae: Single-celled photosynthetic organisms.
So, bacteria is a type of microbe, but there are many other types of microbes out there.