What is the average life expectancy of ancient people?

Primitive society: the average life span of human beings is 15 years old, because human beings are weak and unable to resist natural disasters, diseases and wild animals. The average life expectancy of human beings in BC was only 20 years old, while in ancient times it was only 25 years old. Until this century, the average life expectancy of human beings is only 40 years old. 1700: 35 years old, 1800: 37 years old. It can be seen that the life span of human beings has not increased much in 1700- 1800. The reason is that although disasters such as wild animals can be avoided, there are no effective treatment measures for diseases due to the low level of science and technology. From 65438 to 0985, the average life expectancy in the world reached 62 years. In the future, the average life expectancy of the world population will increase by about one year every five years. 1995-2000 63.9 years old, 2000-2005 65.5 years old, 2005-20/kloc-0 66.8 years old, 2012015 years 68./kloc- By the end of this century, China will become one of the top ten longevity countries in Asia, with an average life expectancy of 72.6 years. ? Experts predict that the average life expectancy of human beings will increase by 95 years in 2300: regional problems, such as Japanese people living longer because of their scientific and technological level and eating habits. Due to diseases such as AIDS, South Africans live shorter lives. There is also the secret of longevity: doctors found that the secret of their longevity is as follows: (1) Open-minded, undisturbed by things, cheerful and optimistic. ? (2) Eat regularly, don't overeat and don't eat too much. ? (3) Taboo alcohol and tobacco. ? (4) Don't sleep too much, don't lose sleep, and live on time. The average sleep time is 7-9 hours. ? (5) Insist on physical exercise and keep fit. ? (6) Drive away loneliness and avoid loneliness. Like flowers, fish, making friends. ? (7) control sexual desire. The development of science and technology affects human life. Some scientists predict that the life span of human beings will reach 300-500 years in the future, but the average life span of human beings will not exceed 100 years in 500 years.