some of which, some of them or some of those? What 's the difference between some of which, some of them or some of those? Theorists realized that physics led to a plethora of new phenomena, ............. defy common sense. 1. some of which 2.some of them 3. some of those The correct answer is 1. but why 2 and 3 is incorrect? Is "which some of them" exactly equal to "some of which"? Thanks.