<h3><u>Answer;</u></h3>
i) Population density
ii) Under population
iii) Over population
Population density 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 because of underpopulation. In low-income nations, overpopulation is one reason for low standard of living.
pipe lines are used world wide
Surprisingly, there are 196 countries today! hope this helped
