Rylan ponderings

Ry was sitting on the toilet looking at a blister on his hand. He asked if he ripped the skin off would it grow back. I told him it would take a few days but his hand would grow some new skin. He then asked, "how come if I cut off my arm, I can't grow a new one?" I didn't want to get into details with stem cells and all that so I said that arms are too big and he can't grow new bones and an arm needs bones. Then he said "If I was a starfish I could grow a new arm"