Parasitism - A close relationship between two organisms in which one organism, the parasite, benefits at the expense of the host organism.⏎
Protozoa - A taxonomic group of single-celled microorganisms that live in almost every kind of habitat and include some pathogenic parasites of humans and other animals. ⏎
Recombinant Technology - The process that allows technicians to create artificial pieces of DNA in which two or more DNA sequences, often from separate organisms, are combined in ways that would not normally occur naturally.⏎
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.⏎