Not quite sure what you're asking, but erosion and deposition do create land forms. For example: erosion along the coastline may result in the formations of arches, stacks, stumps, wave cut platforms, caves, etc. Deposition, different amount of it and in certain areas, under the influence of either destructive or constructive waves, will form beaches - ones with a lot of beach, through a lot of deposition, or slopes beaches where destructive waves have crashed upon the beach. Hope this is what you're looking for.
A. Can help leaders decide how to plan for the future
Whatever fossil is at the lowest layer is the oldest cuz the old fossils lived along time ago and when they died the fossils were buried.