Final answer:
The spacing between FZ level contours in GFAs is not explicitly given, but contour spacing indicates relative differences in elevation. The elevation of the lowest point and the total relief can be determined by examining the contour lines the cross-section line intersects.
Step-by-step explanation:
The question appears to inquire about the spacing between contour lines on a geological feature analysis (GFA). Spacing between contour lines on a map indicates elevation changes within an area. Typically, the closer these lines are, the steeper the terrain. However, the provided information does not indicate a specific spacing value for FZ level contours in GFA's context. Therefore, to determine the elevation of the lowest point along a specified line, look at the contour line with the smallest value that the line crosses. Total relief is the difference between the highest and lowest points along the line, which can be calculated by subtracting the elevation of the lowest point from the elevation of the highest point that the line crosses.