A few years ago I needed a foot x-ray, and on looking at it you could see the granular structure of my foot bones-it wasn't just white for bone, black for not-bone.
12.
As this process occurs, the upper soil material gradually dries out ( because the soil moisture moves from the warm surface layer to the colder layer at the top of the permafrost ) so that it forms a granular structure with many very distinctive crystalline shapes ( such as ice lenses ).
