According to the theory of plate tectonics how do two plates interact to form the largest mountain range

The covers all of earth like a thin shell,but it is not a solid sheet of material.it is broken up into several large sections and many smaller ones. fill in the blank.

Ozone in the upper atmosphere has been depleted by a. sulfur dioxide. b. chlorofluorocarbons. c. carbon dioxide. d. oxygen.

Democratic vs democratic whats the difference? ?