Why do most organisms that die not leave a record of their existence

They leave no record of their existence because it's rare that fossils form. You need the right conditions in which the animal's remains are covered in silt, dirt, and rock layers in order for a fossil to form and therefore preserve the animal's remains in rocks. Otherwise, the animal's remains will be eaten by other animals or eventually rot away. 

The answer is c. they had seedshope this