题目内容：
Passage 3The concept of “environment” is certainly difficult and may even be misunderstood; but we have no handy substitute. It seems simple enough to distinguish between the organism and the surrounding environment and to separate forces acting on an organism into those that are internal and biological and those that are external and environmental. But in actual practice this system breaks down in many ways, because the organism and the environment are constantly interacting so that the environment is modified by the organism and vice versa.
In the case of man, the difficulties with the environmental concept are even more complicated because we have to deal with man as an animal and with man as a bearer of culture. If we look at man as an animal and try to analyze the environmental forces that are acting on the organism, we find that we have to deal with things like climate, soil, plants, and such-like factors common to all biological situational but we also find, always, very important environmental influences that we can only class as “cultural”, which modify the physical and biological factors. But man, as we know him, is always a bearer of culture; and, if we study human culture, we find that it, in turn, is modified by the environmental factors of climate and geography. We thus easily get into great difficulties from the necessity of viewing culture, at one mome
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