[Solved] Which type of sampling is most at risk for sample bias? A) Quota B) Random C) Purposive D) Convenience Valsalva Maneuver: A technique where one attempts to exhale forcefully with a closed mouth and pinched nose, used in medical examinations. Occult Blood: Blood present in such small quantities that it is not visible to the naked eye, often detected through specific tests. External Sphincter: A circular muscle that helps to control the passage of substances out of a body cavity or organ, such as the anus or urethra. Anal Area: The region surrounding the anus, which is the external opening of the rectum, important in the defecation process and subject to various medical conditions.