Final answer:
A security guard performs work to ensure the protection of persons or property, which correlates with the broader protective service industry employing millions in the US.
Step-by-step explanation:
True: A security guard is indeed a person who performs work, usually for compensation, with the primary objective being to guard or patrol an area for the purpose of protecting persons or property. This role fits within the broader protective service industry, which according to the US Bureau of Labor Statistics, employs around three million Americans in various capacities such as police and sheriff's departments, the penal system, security services, parking enforcement, and more.