The answer is A, a mountain building.
The two faces of the book represent the tectonic plates
As he presses them towards each other he is modeling a convergent boundary, and mountains are an affect of convergent plates.
C is the answer just did it
<span>Succession increases biodiversity and helps to prevent too many places from desertification. Without biodiversity, there wouldn't be trees and the other organisms that play a part in keeping an enviroment cool. </span>
