<span>im pretty sure it is Sisak.</span>
Erosion needs Earths rock
Erosion is wearing down and carrying away rocks by wind and moving water, happens faster with steep hillsides and heavy rain
Water and air both have oxygen and due to the contamination in the oxygen both water and air suffer
http://faculty.chemeketa.edu/afrank1/topo_maps/scale.htm use this website and i think this should fully explain it