Evolution - The change in heritable traits in a population of organisms over successive generations.⏎
Epidemic - An often sudden increase in the level of disease in a specific population over a given period of time.⏎
Exoskeleton - An external skeleton that protects and supports an organism, in contrast to an internal endoskeleton.⏎
Encephalitis - Inflammation of the brain, often caused by a virus.⏎