A. War between 2 countries. B. Ways discovered to increase productivity. C. Migration from a continent to another continent. D. A new religion beginning to be accepted by people. 参考答案:B 答案解析:[参考译文]发现什么与人口快速增长有密切的关系 [试题分析]本题考查对相关细节的掌握。 [详细解答]从人类三次重大变化中我们知道每次人口增长都与生产力、和生产方式的提高有关,所以正确答案