Unknown

 The human body is made up of about 60 trillion cells, of which about 400 billion cells die in a day and are born in a day. Even as the second hand of a clock ticks away, the body is undergoing tremendous changes.

Similarly, our eternal lifeforce remains even after our bodies die. Our true "self" runs through the past, present, and future, and the history of this "self" spans billions upon trillions upon quadrillions of years-it is a life with no beginning and no end.