Select all that apply. 1. (1 pt) look at each pair of statements. each statement in the pair is labeled as a cause or as an effect. mark the pair of statements if they are correctly labeled. a. cause: europe's population decreased. effect: the black death attacked europe. b. cause: there were fewer workers. effect: peasants left their manors. c. cause: the manor system crumbled. effect: peasant farmers prospered. d. cause: citict: skilled craftsmen and others moved away from manors.