Parasitism - A close relationship between two organisms in which one organism, the parasite, benefits at the expense of the host organism.⏎
Pathogen - A biological agent that causes disease.⏎
Peptic Ulcer - An open sore that develops on the inner lining of the stomach or upper small intestine.⏎
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.⏎