Difference in objects/object of?

Hi! everyone.
Could someone ,who has read "Poetics by Aristotle", tell me which of the following sentences are correct syntactically and semantically?
The difference in the objects of imitation determines different sorts of literature.
The difference in the object of imitation determines different sorts of literature.
What should there be, the singular one "in the object" or the plural one "in the objects"?
And what about these? Which one is correct in the following?
The difference in the object, medium and manner of imitation determines different sorts of literature.
The differences in the objects ,mediums and manners of imitation determine the sorts of different arts.
I am completely baffled could someone help me out and tell me which of them are possible?
I would be much obliged.