Look at the map of physical features of north america. suppose you were traveling west from the mississippi river to the pacific coast. in terms of elevation, describe the land on your route westward.

Immediately after the Mississippi you'll notice rolling, flat plains in the Great Plains. Then, you'll begin to notice the massive desserts preceding the Rocky Mountains. Finally, you'll come across the lush, green side of the mountains and find yourself at the Pacific Ocean.

Credits to the person above