What was the main focus of the Progressive Era in the early 20th century?

The main focus of the Progressive Era in the early 20th century was to address social issues and promote economic reform. During this period, which spanned roughly from the 1890s to the 1920s, various reform movements emerged in response to the rapid industrialization, urbanization, and immigration that characterized the United States at the time. Reformers sought to tackle problems such as labor exploitation, women's suffrage, child labor, corruption in government, and inequalities in wealth and opportunity.

The movement advocated for changes that would lead to greater equality and justice in society, and it aimed to improve living conditions and provide better protection for the working class. Various social programs, regulations on businesses, and legislation were implemented as a result of this era's reforms, such as the establishment of labor laws and public health initiatives.

In contrast, the other options reflect different historical priorities that were less central during the Progressive Era. Promoting military strength pertains more to later developments in U.S. foreign policy, while the expansion of overseas territories occurred primarily in the late 19th century, particularly with the Spanish-American War. Lastly, while the establishment of public education systems was an important issue, it was not the singular focus of the Progressive Era but rather part