生存就是竞争（英语四级作文）.doc

生存就是竞争（英语四级作文） life is struggle everything in the world is in constant struggle, 'struggle' in the sense of competition in natural selection among organisms. animals and plants struggle for their existence. nature provides them with weapons for that struggle. lions have claws; fish have scales; roses have thorns. they use their weapons for the unavoidable war of existence. nature also orders us to struggle;when we obey nature, we win our existence. the result of struggle is the evolution of a