On a topographic map, contour lines that are close together indicate a steep slope.

Here's why:

* Contour lines represent points of equal elevation.

* Closely spaced contour lines mean that the elevation changes rapidly over a short distance, indicating a steep incline or decline.

* Widely spaced contour lines indicate a gentle slope, as the elevation changes more gradually.

Think of it like this: imagine walking up a hill. If you're walking on a steep part of the hill, you'll be crossing contour lines more frequently.