Death is a permanent cessation of all biological functions that sustain a living being. Anyone that experience biological death can not return to tell what exactly it is to be dead or what happens when one dies because he no longer exist, atleast, not in our visible world. We are composed of a soul possessed by a spirit, clothed in a visible body to experience a physical world made with matter and energy. The spirit is the invisible component that gives life to the soul. The moment a man dies, his soul cease to exist while his spirit returns to his creator and the body returns to the dust (matter) from which it was made. Death is an inevitable fate to everything that lives.
