Which statement is true about contour lines?

Answer: B — They represent equal elevations on the map

Contour lines are a crucial element in topographical maps, as they provide a visual representation of the terrain's elevation changes. The correct statement is that contour lines represent equal elevations on the map. This means that every point along a particular contour line is at the same elevation relative to sea level, which helps in understanding the shape and slope of the land. By illustrating equal elevation, these lines enable users to easily perceive the terrain's features, such as hills, valleys, and slopes. The spacing of the contour lines can also indicate the steepness of the terrain—closer lines signify steeper slopes, while widely spaced lines indicate gentler slopes. In contrast, other statements may suggest inaccuracies or misunderstandings: contour lines do not cross each other because that would imply two different elevations at the same point, which is not physically possible. They are not always straight; they can be curved depending on the topography. Lastly, although contour lines can vary in distance from one another based on the terrain's changes, this is not a defining characteristic of what contour lines represent on a map. Understanding these principles is essential for interpreting topographical maps effectively.