This green and blue planet spinning in space is under severe stress. If we continue to exploit the planet at the present rate，human and animal life will be threatened. Human pride will be followed by nature's punishment. To save our earth and ourselves，we need first develop an unbiased understanding of ourselves，nature and life. Everyone understands the meaning of the sentence“Man should respect animal life and nature”. But the exact meaning of man，nature and animal life is not always clear. Many refer to man and animals as if they were essentially different. I consider man to be an animal and only differing in degree and not in kind from other animals. Although I discuss in conventional terms human rights and animal rights as if they were separate，strictly speaking，human rights should be considered a branch of animal rights. The word“nature”is one of the most complex words in the language，but it has developed three main areas of meaning. These are，first，the essential quality and character of something(as in human nature，or the nature of wood)；second，the inherent force which influences the world(as in Mother Nature)；third，the entire world itself. The last can be taken to include or to exclude human beings. as the phrase man and the natural world implies. I consider humans to be an integral part of nature，although they are also the beings most capable of interfering with its processes. Unfortunately a central drive of Western“man”has been to conquer“nature”. as if it were an object separate from him. Hence it has become connnon to distinguish between what is natural(existing without man's interference)and artificial(man-made). In this way，natural growth is opposed to education，civilization to the natural state. For many urban people living permanently among concrete and glass，nature itself has come to mean little more than the countryside. And this notion of opposition is where the seed of potential destruction lies. The word“unbiased”in Line 3 of Para. 1 means______.