Whats the differnece between "den Apfel" and "die Zeitung"?
Apfel is an apple -- something to eat.
Zeitung is a newspaper -- something to read.
Completely different meanings.
As for the grammar: Apfel is masculine, Zeitung is feminine.
So in the accusative case, we have den Apfel for "the apple" (masculine accusative den) but die Zeitung for "the newspaper" (feminine accusative die).