Which of the following are the three types of contour lines?

The three types of contour lines are essential for understanding topographic maps, and the identification of these lines aids in analyzing terrain and elevation changes effectively.

The correct answer identifies primary, index, and supplementary contour lines. Primary contour lines represent the main elevation changes, typically marked at regular intervals, providing a clear guide for terrain features. Index lines are usually thicker and labeled with elevation values, helping users quickly identify specific heights above sea level. Supplementary lines, on the other hand, are used to show smaller changes in elevation; they are typically drawn between the primary lines and may not have corresponding elevation labels.

This identification and classification of contour lines play a crucial role in map reading and orienteering, making it easier for individuals to visualize the landscape, plan routes, and execute missions effectively in both civilian and military contexts.