Why are secondary sources important to the study of history

How does the grapes of wrath identify the effects of americans' views on the dust bowl? the story is a depiction of oklahoma farmers and the difficulties they experienced migrating to california. the story accurately describes the impact the california vineyard industry had on migrant workers. the story covers the rise of corporate farming and the devaluation of the small family farms that dotted the great plains. the story is an allegory for the conflicts between american values and the rise of the communist party in the united states.

After world war one, how did the allied countries hope to keep germany from becoming too powerful again?

What was the purpose for the georgia colony? to be a cash crop supplier to england to be a buffer between maryland and new jersey to establish a colony for the poor in england