Secondary sources draw on primary sources. They may comment on primary sources, or use the evidence from primary sources to construct an argument. Books or journal articles that analyze, critique, or synthesize a range of sources are examples of secondary sources.
Answer:
The correct answer is: European imperialism brought about many changes in the African continent. Europeans forced Africans to grow cash-crops. This way of growing crops benefited Europeans. ... They also produced a surplus of food, which was used for export and not to satisfy the needs of the starving African people.
Economists have frequently hypothesized that industrialization and its correlates played a major role in inducing fertility decline in the United States after 1850. ... This leaves changes in the cost of raising children as the likely driver of the industrialization result.
