___________occurs in the living body or organism

• A. in vivo
• B. in vitro
• C. Laboratory test
• D. Nonwaived test

Answer: (A)

Where something occurs: inside a living body or organism is described by in vivo. This term means within the living organism, such as measuring a physiological process directly in a patient or observing how a drug acts inside the body. In contrast, in vitro refers to outside the living organism—outside the body, typically in a test tube, dish, or other controlled lab environment (for example, cells grown in culture or chemical reactions performed in a glass container). A laboratory test is a broad label for any test done in a lab and doesn’t specify whether it happens inside or outside the body. A nonwaived test relates to regulatory categories on complexity, not location of where the process takes place. Therefore, the phrase describing a process occurring inside a living organism is in vivo.