Infection - The entry, establishment, and replication of pathogens inside a host organism.⏎
Germ Theory - A theory in medicine stating that microorganisms are the causative agents of infectious, contagious diseases.⏎
Habitat - The specific geographical area or physical environment that is inhabited by an organism or a population of organisms.⏎
Metabolism - The sum total of chemical reactions that occur within a living cell both to build new molecules within the cell and break down and assimilate sources of energy for the cell.⏎
Microbe - Sometimes referred to as a microorganism, a microbe is an organism that is microscopic and thus invisible to the naked eye.⏎