Answer:
because it permits certain movement of molecules in and out of the cell
Some of the physiographic features that cause extreme aridity may be found together within a <span>single desert, but t</span>he deserts found in the western united states are primarily the result of being located within the rain shadow of one or more mountain ranges.
Contour lines determine the steepness of the land by how close they are together. Generally, contour lines rise to a particular scale (e.g. a line for every ten metres), therefore, if the contour lines are closer together then the height of that particular area has risen more steeply than if the contour lines are further apart where the steepness has increased more gradually.
