Question

______ is the number of people living in a square mile. In the future, economically developed nations may not have enough money to take care of older citizens due to . In low-income nations, is one reason for the low standard of living.

Answer 1

Population density

Step-by-step explanation:

Because population density is the number of people living in a square mile.In the future,economically developed nation may not have enough money to take care of older citizens due to. In low income nations,is one reason for the low standard of living.

The answer will be population density