Which statement best describes intermediate contour lines on a topographic map?

• A. They have elevation numbers
• B. They have no numbers and appear between index contour lines
• C. They are dashed lines indicating approximate elevations
• D. They are solid lines with large elevation increments

Answer: (B)

Contour lines show elevation, and the ones that carry numbers are the index contours—heavier lines that label a specific height. Intermediate contour lines fill the gaps between those numbered lines to show smaller steps in elevation. They are drawn as solid lines without numbers, so you infer the exact height by knowing the labeled line you’re counting from. This arrangement makes the map detailed enough to see how the terrain rises or falls without cluttering the map with a number on every line. Dashed lines and lines with large elevation jumps don’t describe intermediate contours, which is why the statement that intermediate lines have no numbers and appear between index contours is the best description.