This pattern is important to notice. Not only does it put the current problems of demographic growth into a historical perspective, but it suggests that the cause of rapid increase in population in recent years is not a sudden enthusiasm for more children, but an improvement in the conditions that traditionally have caused high mortality.

　　Demographic history can be divided into two major periods: a time of long, slow growth which extended from about 8,000 BC. till approximately AD. 1650. In the first period of some 9600 years, the population increased from some 8 million to 500 million in 1650. Between 1650 and the present, the population has increased from 500 million to more than 4 billion. And it is estimated that by the year 2000 there will be 6.2 billion people throughout the world. One way to appreciate this dramatic difference in such abstract numbers is to reduce the time frame to something that is more manageable. Between 8000BC and 1650, an average of only 50,000 persons was being added annually to the worlds population each year. At present, this number is added every six hours. The increase is about 80,000,000 persons annually.

　　1. Which of the following demographic growth pattern is most suitable for the long thin powder fuse analogy?

　　A. A virtually stable or slightly decreasing period and then a sudden explosion of population.

　　B. A slow growth for a long time and then a period of rapid, dramatic increase.

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