Final answer:
The word 'runs' in the context of the Fall Line from Columbus to Augusta describes the Fall Line's geographical span across an area, marking the transition from the higher Piedmont to the lower Coastal Plain.
Step-by-step explanation:
The term "runs" as used in the sentence refers to the Fall Line travelling or extending through an area, specifically, the geological border that spans from Columbus to Augusta. This feature signifies the natural transition between the Piedmont region, which has a higher elevation, and the Coastal Plain which is at a lower elevation, eventually meeting sea level. The Fall Line is characterized by the presence of boulders, rapids, and a significant drop in elevation which can create barriers for navigation and development, influencing historical settlement patterns and the location of cities.