Death

Who is dying? Who's death are we afraid of ? Are we alive after death ?
Everytime we take in breath, life is in the body. When breath goes out body is dead. But you are alive. In deep sleep the 'i' dies. You are not there. When you wake up , you come back to life. So why are you afraid of death. After every breath that goes out, some cells die. Human liver becomes a new regenerated organ every three months. We get a brand new brain every 6 months. old cells die, new cells are born. So what is death. What are we afraid of.