Final answer:
The NAACP, founded in 1909 to fight against racial discrimination, had grown to about 90,000 members by 1920, establishing itself as a major civil rights organization.
Step-by-step explanation:
The National Association for the Advancement of Colored People, better known as the NAACP, was founded in 1909 as a response to the persistent racism and violence against African Americans, specifically the race riot in Springfield, Illinois. By 1920, the NAACP had grown significantly in membership as it worked to oppose segregation and fight for civil rights, thanks in part to the efforts of leaders like W.E.B. Du Bois. By the year 1920, the NAACP had approximately 90,000 members, making it the leading civil rights organization at the time.