Parasitism - A close relationship between two organisms in which one organism, the parasite, benefits at the expense of the host organism.⏎
Respiratory Tract - The part of the anatomy that has to do with the passage of air and includes the nose, larynx, trachea, and lungs.⏎
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.⏎