[Solved] Discuss why U.S. organizations must be very careful when dealing with issues relating to pornography in the workplace. Endocarditis: An infection of the inner lining of the heart chambers and heart valves. Singular: Unique or one of a kind; in grammar, referring to the form of a noun or pronoun that denotes only one person, place, thing, or idea. Plural: The form of a word used to denote more than one. Cardiomyopathy: A group of diseases that affect the heart muscle, leading to decreased heart function.