Final answer:
Contour lines on a mountain are closely spaced, reflecting steep terrain, whereas in a broad, flat valley, the lines are widely spaced, indicating gentle slopes. Mountains may show complex patterns with closed loops, unlike the simpler contours in flat valleys.
Step-by-step explanation:
One primary difference between contour lines on a mountain compared to those in a broad, flat valley is the spacing of the lines. On a mountain, contour lines will be closely spaced, indicating steep terrain, as the elevation changes rapidly over a short horizontal distance. Conversely, in a broad, flat valley, the contour lines will be widely spaced, suggesting a gentle slope or relatively flat terrain, where elevation changes very gradually over a larger horizontal distance.
In mountainous areas, contour lines may form closed circles or loops, showing the summits of hills or peaks, while valleys are often indicated by a 'V' pattern, with the point of the 'V' pointing upstream. In contrast, flat valleys might not display such drastic patterns and may exhibit more simplified contours that stretch out across wide areas with minimal curvature.