Final answer:
Lincoln Steffens's and Ida Tarbell's writings are examples of investigative journalism that exposed corporate and political corruption in the early 20th century, leading to significant societal reforms.
Step-by-step explanation:
Lincoln Steffens's The Shame of the Cities and Ida Tarbell's The History of the Standard Oil Company are prime examples of investigative journalism. Steffens and Tarbell, alongside other writers such as Ray Stannard Baker, were part of a group commonly referred to as muckrakers—journalists who aimed to expose corruption and wrongdoing in society during the early 20th century. Tarbell's meticulous research and publication of articles on Standard Oil ultimately contributed to the break-up of John D. Rockefeller's powerful monopoly, just as Steffens's exploration of city politics shed light on corruption within urban governance.