On topographic maps, how does the spacing of contour lines relate to continental and ocean-floor topography? a. for both continental and ocean-floor topography, gentler slopes are represented by widely spaced lines while steeper slopes are represented by closely spaced lines. b. only closely spaced lines are used to represent continental topography, while only widely spaced lines are used to represent ocean-floor topography. c. for both continental and ocean-floor topography, steeper slopes are represented by widely spaced lines while gentler slopes are represented by closely spaced lines. d. only widely spaced lines are used to represent continental topography, while only closely spaced lines are used to represent ocean-floor topography.