slow changes to the Earth by ice
Hello, W.E.D in the title above stands for weathering, Erosion, and Deposition. I bet you thought it was about a wedding, but no. Weathering is the breaking off of Earths crust. Erosion is the moving around of Earths crust. Deposition is the depositing of Earths weathered crust. Just as simple as that.
Glaciers are slow moving giant pieces of ice that scrape the ground and pick up loose eath materials as they move and melt over thousands of years.