What do contour lines on a map indicate?

Contour lines on a map indicate points of equal height above or below sea level. These lines are a fundamental tool in topographic mapping, allowing users to visualize the elevation and shape of the terrain. Each contour line connects locations that have the same elevation, which helps in understanding the slope and steepness of the land. When contour lines are close together, it signifies a steep incline, whereas lines that are spaced further apart indicate a gentler slope. This information is particularly useful for activities such as hiking, planning construction, and understanding geographical features.

The other choices do not accurately describe the function of contour lines on a map. Roads and pathways, buildings and structures, and vegetation zones are represented by different symbols and markings, not by contour lines, which specifically convey elevation data.