As of 2023, Japan has the highest life expectancy at birth, with an average of 84.6 years for women and 79.6 years for men.

Population aging refers to the increasing proportion of older adults (typically defined as those aged 65 or older) in a population.

Population aging typically brings challenges such as increased healthcare costs, shortage of skilled workers, and increased demand for eldercare services. Higher productivity is not a common challenge associated with aging.

Rural-to-urban migration refers to the movement of people from rural areas to urban areas.

Improved healthcare, better nutrition, and increased physical activity have all contributed to the increase in life expectancy over the past century.

Old age is the term used to describe the age at which a person is considered elderly. The specific age at which a person is considered old varies across cultures and societies.

China has the largest population of people aged 65 and older, with over 190 million individuals in this age group.

Extended working life refers to the phenomenon where older adults continue to work past the traditional retirement age.

Population aging can lead to challenges such as increased demand for healthcare services, shortage of skilled workers, and increased government spending on pensions. Increased economic growth is not a potential consequence of population aging.

Urban-to-rural migration refers to the movement of people from urban areas to rural areas.

Increased access to education, improved healthcare, and later age at marriage have all contributed to the decline in fertility rates in many countries.

Adulthood is the term used to describe the age at which a person reaches full physical and mental maturity.

As of 2023, the Central African Republic has the lowest life expectancy at birth, with an average of 49.6 years for both men and women.

Migration is the term used to describe the process of people moving from one country to another.

Population aging can bring challenges such as increased healthcare costs, shortage of skilled workers, and increased government spending on pensions. Increased economic growth is not a potential benefit of population aging.