Germ Theory - A theory in medicine stating that microorganisms are the causative agents of infectious, contagious diseases.⏎
Interferon - A type of protein produced by cells of the immune system that help keep viruses, bacteria, and cancer cells from growing.⏎
Immune System - The system of biological structures and processes that protects the body from foreign substances, including pathogens.⏎
Microbe - Sometimes referred to as a microorganism, a microbe is an organism that is microscopic and thus invisible to the naked eye. ⏎
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.⏎