Valleys
A valley is a depression or large hollow that is able to be drained externally. It also can be a plain area such as the Mississippi valley. A stream or a river tend to lie at the bottom of the valley. The valley is created in a number of ways. First is by erosion from glaciers or water, such as the remaining river or stream. Another manner of creation is when the land is lowered through the activity of geological faults.
Plateaus
Plateaus are found in the ocean and on land. They are similar to mountains in that they are projections of the ground with at least one side that is a steep slope. Unlike mountains, the summit of a plateau is relatively flat and has a greater mass area. It is possible to have basins and low areas within the plateau. Depending on the height of the plateau, the climate can vary differently from the surrounding area with a tendency to be dry and arid. Some plateaus are formed by a succession of lava flows.
Mountains
A mountain is a huge projection from the earth's surface. The slopes are steep and abrupt. A mountain is higher than a hill, that being a height greater than 2,000 feet. Mountains occur singularly or in ranges, such as the Appalachian or the Rockies mountain ranges in the United States. They are formed by volcanic activity, erosion or when two tectonic plates collide.
Canyons
Canyons are deep valleys that exist below the rim of a landform, usually a plateau. A canyon is created over thousands of years as rain, ice, water and wind take their toll on the soil and ebb it away. According to Science Clarified, the depth of a canyon can be greater than its width.