Question

contour lines never cross except at cliffs. *
true
false

every 5th contour line is an index contour line and will indicate an elevation. *
true
false

Explanation:

1. For the first question: Contour lines represent constant elevation. A single point cannot have two different elevations unless it's a vertical cliff, where the same point is part of two different elevation levels, so contour lines can cross here.
2. For the second question: Index contour lines are defined as every 5th contour line on a topographic map, and they are labeled with a specific elevation value to make reading map elevations easier.

Answer:

1. True
2. True