What factors led to “catastrophic changes” in Africa? pls answer

Read the excerpt from frederick douglass’s speech “what to the slave is the fourth of july? ”go where you may, search where you will, roam through all the monarchies and despotisms of the old world, travel through south america, search out every abuse, and when you have found the last, lay your facts by the side of the everyday practices of this nation, and you will say with me, that, for revolting barbarity and shameless hypocrisy, america reigns without a rival.which of the following  best  describes douglass’s word choice in this excerpt?