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.⏎
Prion - A causative agent of infectious disease that is composed primarily of protein.⏎
Parasitism - A close relationship between two organisms in which one organism, the parasite, benefits at the expense of the host organism.⏎
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.⏎
Reservoir - An organism in which a parasite that is pathogenic for some other organism lives and reproduces without harming its host.⏎