Final answer:
A series of closed contour lines most likely represents a valley. Contour lines are used in topographical maps to represent changes in elevation.
Step-by-step explanation:
A series of closed contour lines most likely represents a valley. Contour lines are used in topographical maps to represent changes in elevation. Closed contour lines that are close together indicate a steep terrain, such as a valley. For example, on a topographical map, if the contour lines form concentric circles, it suggests the presence of a valley.