Which of the following is a type of contour line?

The type of contour line relevant to this context is one that connects points of equal value, typically representing elevation on a topographic map. Choosing "Supplementary" may reflect a misunderstanding, as it generally refers to additional information rather than a specific type of contour line.

In mapping, contour lines serve to illustrate the terrain, indicating where the land rises and falls. "Constant" would refer to lines indicating values such as constant elevation, temperature, or other measurements, showcasing a fundamental aspect of contour lines. Each of these lines may depict variations across a landscape but the focus here on "Constant" as it relates to measurement provides clarity on the function of contour lines in visualizing geographical features.

Understanding the concept of foundational contour lines helps in navigation, land use planning, and geographic analysis, emphasizing the relationships among terrain features through mapping.