Final answer:
In summer 1945, Jackie Robinson was playing for the Kansas City Monarchs in the Negro Leagues. His move to the Brooklyn Dodgers in 1947 marked the end of racial segregation in Major League Baseball. Besides his contributions to sports, Robinson also played a key role in the civil rights movement.
Step-by-step explanation:
In the summer of 1945, Jackie Robinson was playing for the Kansas City Monarchs in the Negro Leagues. However, Jackie Robinson's sporting career took a significant turn when he started playing for the Brooklyn Dodgers in 1947, making him the first African American to break color barriers in Major League Baseball. His integration into mainstream baseball paved the way for other African American athletes to challenge the segregation in American sports. Jackie Robinson had a significant influence not just as a successful baseball player, but as an active participant in the civil rights movement.
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