Supplementary contours are shown where and how?

• A. Shown on maps of flatter areas to show features less than the basic interval; shown as dashed or dotted lines
• B. Solid lines in mountainous regions
• C. Blue circles
• D. Green shading

Answer: (A)

Supplementary contours are used to reveal small elevation changes in flat terrain that between the regular contour lines would be missed. They’re drawn as dashed or dotted lines between the main contours, so you can see subtle rises or dips that lie within the basic contour interval. This helps convey gentle relief more accurately in flat areas. The other options don’t fit this purpose: supplementary contours aren’t represented by blue circles or green shading, and in mountainous regions the map typically relies on solid contour lines rather than these extra dashed lines.