Potatoes need sun, water and soil
The rivers start from the mountains or hills.
So to me it looks like that into more of the future more people are born in Urban areas and in the Rural areas it looks like it will slowly go down till there is little to none left.
The texture of sedimentary rocks, like the size of grains or chemical precipitates can show how the rock was formed. The fossils of sedimentary rocks can show when the rock was formed. The stratification and sorting of the particles can show were the rock was formed.
