Question

what type of lines describe the vertical aspect of an undulating ground surface?
legal site boundaries
dashed lines
hidden lines
contour lines

Explanation:

Contour lines are used in cartography to represent elevation changes on a map, which directly relate to the vertical aspect of an undulating ground surface. Legal site boundaries define property limits, dashed lines often indicate hidden or non - visible edges in technical drawings (not specific to ground surface verticality), and hidden lines show edges not visible in a particular view (also not for ground surface verticality).

Answer:

Contour lines