今日の読み物　レベル12

◇早稲田大・人間工学など

For the first time, humanity as a whole is growing older. The demographic aging of the population began early in this century with improvements in the survival of infants, children and women of childbearing age. It will end near the middle of the next century when the age composition of the population stabilizes and the practical limits to ...レベル15 [早稲田大・人間工学]