Upton Sinclair, Frank Norris, and Ida Tarbell
made their greatest contributions to the
Progressive movement by
(1) working to end political corruption in cities
(2) speaking out for the equal rights of Hispanic
Americans
(3) supporting legislation to improve tenement
housing
(4) publishing books and articles to expose the
problems of society



Answer :

Upton Sinclair, Frank Norris and Ida Tarbell made their greatest contributions to the Progressive movement by (4) publishing books and articles to expose the problems of society. Upton Sinclair wrote a book which showed the dangerous and unsanitary lives workers of the Meatpacking District went through on a daily basis, Frank Norris exposed the struggle railroad workers go through with their bosses and the unfairness of the railroad workers life in California and Ida Tarbell wrote about the manipulative men behind the oil trade.