Final answer:
The NAACP worked to remove legal barriers that separated white and black Americans by challenging segregation through the courts and advocating for equal rights.
Step-by-step explanation:
The NAACP was established in 1909, stemming from the Niagara Movement, and strived for political, social, economic, and educational equality for minority groups in America. It focused on overturning Jim Crow laws through legal challenges, making monumental strides against segregation in education and striking down the legality of discriminatory practices like the Grandfather Clause. The NAACP's efforts were aimed at affirming the rights guaranteed by the 14th and 15th Amendments.
In contrast, the UNIA, founded by Marcus Garvey, largely focused on promoting black pride and economic self-sufficiency, which though important, did not directly challenge legal segregation as the NAACP did. The UNIA also provided a platform for economic ventures and fostered pride through African heritage education. However, their focus was not on dismantling legal barriers but rather on building an independent, self-sufficient black community. While both organizations had significant impacts on African American history, the NAACP was principally responsible for the legal challenges that addressed racial segregation.