I would like to guess the answer is distilled water but I'm not positive
It would most likely be the last one. Erosion is effectively the process of natural forces breaking down rock or soil, which allows it to move from place to place with the aid of forces like wind or water. I would say the answer would be the first one, but it only says rock, while erosion can affect more than just rocks. Hope this helps.
Answer: contour lines.
Topographic maps are easily recognized by their contour lines.
Use the forumla y=Mx+b and rise over run when plotting it on the graph for each example
