Final answer:
Florence Kelley, Upton Sinclair, and Jacob Riis are similar in that they all worked to expose economic and social abuses, leading to significant societal reforms in areas such as child labor, food safety, and housing conditions.
Step-by-step explanation:
One way in which Florence Kelley, Upton Sinclair, and Jacob Riis were similar is that each sought to expose economic and social abuses. Florence Kelley focused her efforts on ending child labor, recognizing it as detrimental to children as well as a potential health hazard to middle-class families through contaminated products.
Upton Sinclair, on the other hand, gained recognition through his novel The Jungle, which exposed the deplorable conditions in the Chicago meatpacking industry, leading to significant food safety reforms. Jacob Riis utilized his skills in photojournalism to reveal the harsh realities of life in tenement slums, compelling the public and policymakers to take action to improve living conditions. Their collective work underscored Progressive ideals like social justice, public health, and regulatory reforms, contributing to the era's reputation for social activism.