Peptic Ulcer - An open sore that develops on the inner lining of the stomach or upper small intestine.⏎
Rheumatic Fever - An inflammatory disease that may be caused by an untreated or improperly treated case of strep throat.⏎
Reservoir - An organism in which a parasite that is pathogenic for some other organism lives and reproduces without harming its host.⏎
Natural Selection - The process by which certain heritable traits that contribute to the survival and reproductive success of an organism become more widespread within a population over successive generations.⏎