Old Answer: Nothing, that is a personal belief, not a proven fact.
My Answer: What i have heard over my years of life (which i have talked to a few ghost hunters named Nick groff, Zak Bagans, and Aaron Goodwin Ghost Adventures) They have said its because they have not been put to rest yet and you have to have a spiecial person to get rid of a ghost.
Sometimes they come back to life sometimes not
they come to life when you take a pic. or that's just the ghost itself
Ghosts are not real. Whoever said this is..............nvm. Stop wasting time worrying about this and live your life!
It will not come back to life.
no he does not come back to life on drawn to life but he does come back on drawn to life the next chapter.
No. It is impossible for anything to come back to life.
well you can come back to life but as an animal or a baby
No. Once something dies they can never come back to life.
Jesus did come back to life, but if he didn't we wouldn't know he was going to come back again to judge us
It's a little complicated as Harry had the Reserection stone before he "died" and he brought back Lily, James, Sirius, and Lupin. They didn't actually come back to life and were alive again, they came back as lively ghosts to talk to Harry.
Gohan did be brought back to life
No frozen things are dead and they don't come back to life.