According to paragraph 3, which of the following statements best describes the difference between structure and composition? A. "Structure" refers to the arrangement of plant material above the ground surface; "composition" refers to the arrangement of root tissues below the surface of the ground. B. "Structure" refers to the age of the forest; "composition" refers to the forest's nature. C. "Structure" refers to the arrangement of plant species in an area, "composition" refers to which plant species are present in the area. D. "Structure" refers to the shape of the forest canopy; "composition" refers to the number of crowns forming the canopy.