Dramatic gains in in prosperous nations have contributed to emerging adulthood.

Dramatic gains in life expectancy in prosperous nations have contributed to emerging adulthood. The term life expectancy is a statistical measure of the average time an organism is expected to live, based on the year of its birth.
In recent years population has experienced substantial gains in life expectancy. People are living much longer worldwide than they were two decades ago. Several factor contributed to this: people are more educated and know how to maintain and care for their health, the medicine  is better and better, the technology also..