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建议用时：15分钟 A [2015·重庆一中一诊]The African elephant, the largest land animal remaining on earth, is of great importance to African ecosystem (生态系统). Unlike other animals, the African elephant is to a great extent the builder of its environment. As a big planteater, it largely shapes the forestandsavanna (稀树草原) surroundings in which it lives, therefore setting_the_terms of existence for millions of other animals that live in its habitat (栖息地)． It is the elephant's great desire for food that makes it a disturber of the environment and an important builder of its habitat. In its continuous search for the 300 pounds of plants it must have every day, it kills small trees and underbushes, and pulls branches off big trees. This results in numerousopen spaces in both deep tropical forests and in the woodlands that cover part of the African savannas. In these open spaces are numerous plants in various stages of growth that attract a variety of other plant eaters. Take the rain forests for example. In their natural state, the spreading branches overhead shut out sunlight and prevent the growth of plants on the forest floor. By pulling down trees and eating plants, elephants make open spaces, allowing new plants to grow on the forest floor. In such situations，the forests become suitable for large hoofed plant eaters to move around and for small plant eaters to get their food as well. | 
