Final answer:
Jane Addams and Lincoln Steffens are best known for their contributions to easing the problems of the urban poor during the Progressive Era, with Addams establishing Hull House and advocating for social reforms, and Steffens exposing social injustices through muckraking journalism.
Step-by-step explanation:
Lincoln Steffens and Jane Addams are most notably associated with attempting to ease the problems of the urban poor. Jane Addams, a pioneering social worker, established Hull House in Chicago in 1889, which was part of the settlement house movement.
These settlement houses provided education and social services to the urban poor, especially immigrants. They also advocated for reforms like child labor laws and worker's compensation. Lincoln Steffens, while less directly involved in social services, was a key muckraker whose journalism helped to expose social injustices, including issues affecting the urban poor. Their contributions, as part of the Progressive Era's push for social reforms, were instrumental in improving the living conditions and legal protections for many disadvantaged Americans.