Why did African American professionals such as doctors , businessmen and journalists join together to form organizations.?

At the beginning of the twentieth century, there were approximately 270,000 native americans left in the united states. according to the 2000 census, there are now four million native americans living in the united states. better treatment of native americans is credited with this population increase. discuss how the indian reorganization act and the indian self-determination and education assistance act aim to improve the lives of native americans in the united states.