turning purple once more , kizzy chewed her lip and finally said , `` well , freshman year , before i learned not to participate in class discussions , we were talking about human nature or something in life science , and this girl heather black starts saying how humans are the only violent species , and how noble the animal kingdom is , blah-de-blah-blah , only killing for food , and the only species that has , like , war and murder and rape , is humans . ''