What are the social classes in the film Grapes of Wrath?

In "The Grapes of Wrath," social classes are primarily represented through the struggles of the Joad family, who belong to the impoverished migrant worker class. They face harsh conditions and exploitation as they travel to California in search of work during the Great Depression. In contrast, the wealthy landowners and agribusinesses represent the upper class, often indifferent to the plight of the migrants and prioritizing profit over human welfare. The film highlights the stark divide between these classes and the resulting social injustice and despair.