Answer:
Aging populations
Explanation:
The industrialized countries are facing a big demographic problem in the past few decades. The problem is the aging population. The living conditions in this countries are the best in the world, so they have high life expectancy, and while that is good, a problem occurs because the birthrates are very low. The birthrates are so low that they can not even simply sustain the same number of the population. This situation leads to fewer and fewer young people, and more and more elderly people, so the population pyramid is becoming wider at the top and narrower at the bottom.
Slaves fled to Canada to gain freedom, so the Canadian population grew.
