Answer:
Fossils
Explanation:
Fossils are the remains or trace of a living organism in the past. After an organism dies as time passes the soil over the body starts to increase. It can be assumed that more the depth the older the organism.
The ancient Greek philosophers deduced that fossils were once living beings. Aristotle noticed that the fossil seashells were similar to the ones that were found on the beach. This made him think that fossils were once living.