［A］ New plants and animals then move into the area and begin to grow.
- A［B］ Just 2 percent of the sunlight goes through the many layers of leaves and branches above, so understory plant species have developed special traits to cope with low light levels.
- B［C］ On a smaller scale, large mammals, such as elephants, regularly destroy rain forest vegetation in the Congo River Basin in Africa.
- C［D］ An understory of shorter trees and a lacework of woody vines, or lianas, produce a forest of such complex internal architecture that many animals, including some sizable ones, rarely or never descend to the ground.
- D［E］ Less than one percent of the trees in the forest reside in the canopy and emergent layers.
- E［F］ Because more light penetrates the canopy, however, the vegetation of the understory and forest floor is better developed than in the tropics.
- F［G］ The rich, green canopy is teeming with life, and forest researchers have developed ingenious methods for accessing this mysterious ecosystem.