Which statement best describes what contour lines indicate?

• A. Contour lines indicate elevation with respect to Mean Sea Level
• B. Contour lines indicate political boundaries
• C. Contour lines indicate population density
• D. Contour lines indicate land use

Answer: (A)

Contour lines connect all points that share the same height above mean sea level, so they display elevation on a map. Each line represents a specific elevation, and the spacing between lines shows how steep the terrain is: lines that are close together indicate a steep slope, while lines that are far apart indicate a gentler slope. These lines are not about political boundaries, population density, or land use, which are shown by different kinds of maps or data layers.