题目内容：
Pesticides (杀虫剂)Where do pesticides(杀虫剂)fit into the picture of environmental disease? We have seen that they now pollute soil, water, and food, that they have the power to make our streams fishless and our gardens and woodlands silent and birdless．Man, however much he may like to pretend the contrary, is part of nature．Can he escape a pollution that is now so thoroughly distributed throughout our world?
We know that even single exposures(暴露)to these chemicals, if the amount is large enough, can cause extremely severe poisoning．But this is not the major problem．The sudden illness or death of farmers, farm workers, and others exposed to sufficient quantities of pesticides are very sad and should not occur．For the population as a whole, we must be more concerned with the delayed effects of absorbing small amounts of the pesticides that invisibly pollute our world.
Responsible public health officials have pointed out that the biological effects of chemicals are cumulative(积累的)over long periods of time, and that the danger to the individual may depend on the sum of the exposures received throughout his lifetime．For these very reasons the danger is easily ignored．It is human nature to shake off(摆脱)what may seem to us a threat of future disaster．"Men are naturally most impressed by diseases which have obvious signs," says a wise physician, Dr．Rene Dubos, "yet some of their worst enemies slowly approach them unnoticed．"Which of the following is closest in meaning to the sentence "Man, is part of nature．"(Line 3～4, Para．1)? A．Man appears indifferent to what happens in natur
B．Man acts as if he does not belong to natur
C．Man can avoid the effects of environmental pollutio
D．Man can escape his responsibilities for environmental protectio
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