Final answer:
Fire patterns, specifically charring, indicate where fuel burned on floors during a fire. These marks help determine the fire's origin and progression.
Step-by-step explanation:
The indication of where fuel burned on floors during a fire can be identified by fire patterns. These are visible marks or effects left by the fire as it burns, which can show the origin and progression of the fire. Charring on floors is one such fire pattern that can be observed after a fire has been extinguished. It is the result of the combustion process where materials have been partially consumed by fire, leaving behind blackened areas that indicate where the fire burned most intensely.
While debris and flashover are also associated with fires, they do not directly indicate the location where fuel burned. Debris refers to the scattered remains after a fire, and flashover is a near-simultaneous ignition of most of the directly exposed combustible material in an enclosed area.