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.⏎
Peptic Ulcer - An open sore that develops on the inner lining of the stomach or upper small intestine.⏎
Prion - A causative agent of infectious disease that is composed primarily of protein.⏎
Protein - Large molecules composed of one or more chains of amino acids in a specific order determined by the base sequence of nucleotides in the DNA coding.⏎
Pathogen - A biological agent that causes disease.⏎