As a country develops,the inhabitants usually become wealthier-and healthier They have better health care,drink cleaner water,and eat better food. Both men and women can expect to live longer. For example,table a shows that in Japan the average life expectancy at birth for men is 81.4 years,and for women is 87.5 years. On the other hand,in a developing country like Zambia,it is just 38.5 for men and 38.7 for women.