Answer to Question 1
In large part Latin America exhibits urban dominance and primacy because a few key cities, during the colonial period, were the principal locations of investment. Following independence, these select cities continued to receive the lion's share of investment; rural-to-urban migration patterns intensified the concentration of population in these cities.
Answer to Question 2
There are two sources of heat in the Earth's interior:
i. radioactivity decay
ii. residual heat from Earth's formation
