Final answer:
The principle where each firefighter reports to only one supervisor is called Unity of Command. It's part of an organization's hierarchy of authority, ensuring a clear and manageable chain of command.
Step-by-step explanation:
The principle that states each firefighter answers to only one supervisor is known as Unity of Command. This principle is part of the hierarchy of authority within an organization, ensuring a clear chain of command. For instance, in a retail setting like Walmart, an employee would report to a shift manager, who in turn reports to the store manager, and so on, illustrating how every member of the organization follows this structured chain.