The correct answers are B) the growth of cities, C) Migration to Canada, the United States, Australia, and New Zeland, and D) an increase in the use of coal.
<em>The consequences of rapid population growth in the 20th century are “the growth of cities, migration to Canada, the United States, Australia, and New Zeland; and an increase in the use of coal.
</em>
A notorious global trend after World War II is migration and the growth of large cities. After the war and even today, people are looking for better living conditions for their families. First-world countries are very attractive for immigrants, and that is the case of Canada, the United States, Australia, and New Zeland. Larger cities contain diverse industries where people can get better jobs. And regarding coal, this mineral was used in industries as fuel for machines until electricity and oil substituted ist use in the industry.