What major concept did Muckrakers expose during the Progressive Era?

Muckrakers played a pivotal role during the Progressive Era by investigating and exposing government corruption and social injustices, which were significant issues affecting American society at the time. They brought to light various problems such as political corruption, the exploitation of labor, unsafe working conditions, and the plight of the impoverished. Through their journalistic efforts, muckrakers informed the public about these critical issues, driving a demand for reforms. Their work led to increased awareness and eventually legislative changes aimed at addressing the rampant corruption and social inequalities that were prevalent during this period. This focus on unveiling the darker aspects of society helped to galvanize the Progressive movement, which sought to improve conditions for all citizens and foster a more equitable society.