Final answer:
Social-conflict theory explains that public education became more important in the late nineteenth century due to the demand for a skilled workforce, according to factory owners. Conflict theorists argue that public schools reinforce social inequalities and serve the existing power structures. Technological advancements and an increasing population in urban areas influenced the growth of public education in the United States.
Step-by-step explanation:
Social-conflict theory explains that in the United States, public education became more important in the late nineteenth century when factory owners needed a skilled, obedient, and disciplined workforce. Conflict theorists believe that public schools reinforce social inequalities based on class, gender, race, and ethnicity, and serve to maintain the existing power structures. The demand for workers in urban areas with technological advancements like electricity and skyscrapers contributed to the growth of public education to meet the needs of the emerging middle class.