Why would South America and Africa have no urban regions

Because the total area of those two countries are too massive to populate and some of the environments are inhospitable.

Explanation:

because the two continents have most of their population in rural places and most of the countries in those 2 regions have a smaller GDP and economic growth so they don't really invest into a more urban society. another reason is a lot of those countries owe a lot of debt to the world bank. But most importantly their culture is more focused on livestock and farming  

Explanation:

d.

thist title points out that you are explaining the nature of the u.s. government. it is the most specific. a representative government consists of a government where decisions are taken according to a voting system. the most essential aspect of a representative government is found in the different structures where voting rights are granted to different groups of people. for example, voting for governor, mayor, president, local police chief etc.