What types of sources do historians use to learn about the past

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.

What is zinn's approach to the study of history? what does he suggest occurs when history is told is the story of human progress?

The factory system of the early-19th century caused a) a decrease in farm production. b) an increase in rural population. c) an increase in urban population. d) high unemployment in other areas.