Exoskeleton - An external skeleton that protects and supports an organism, in contrast to an internal endoskeleton.⏎
Endemic - The baseline level of disease usually present in a community.⏎
Contagion - A general term for any disease-causing infectious agent spread by direct or indirect contact.⏎
Epidemic - An often sudden increase in the level of disease in a specific population over a given period of time.⏎
Gene - The physical and functional unit of heredity made up of DNA. Every individual has two copies of each gene, one inherited from the mother and the other from the father.⏎