What is the purpose of a comparison/contrast?

Explain the effect of the rhetorical questins for the below paragraph."i pinched myself: was i still alive? was i awake? how was it possible that men, women, and children were beiing burned and that the world kept silent? no. all this could not be real. a nightmare soon i would wake up with a start, my heart pounding, and find that i waas back in the room of my childhood, with my "