(I) Lake and ocean shores have extensive sand dunes, which are deposited by wind and water. (II) At first these dunes are blown about by the wind. (III) The sand dune environment is severe, with high temperatures during the day and low temperatures at night. (IV) If ozone disappeared from the stratosphere, Earth would become unlivable for most forms of life. (V) Also, sand dunes are deficient in certain mineral nutrients needed by plants.