Let me just tell you first before I start, The spelling should be fantasy not fantacy :D
Okay so here is an example for Fantasy:
The fish is walking in the store.
why is that a fantasy?
because a fish can't walk in real life. Fishes swim.
Now, here's an example for Reality:
The girl is eating food.
why is it realistic?
because a girl can really eat in real life.
ok so let me explain again about Reality and Fantasy
Reality is that could really happen in real life.
Fantasy is about things that could never happen in real life.