What are the preserved remains of ancient organisms called?

The preserved remains of ancient organisms are called fossils. A fossil may preserve part of an organism, such as a bone, tooth, shell, or leaf, or it may record an organism's activity through a track, burrow, or fossilized feces.

Fossilization usually begins when remains or impressions become rapidly buried by sediment. Over time, minerals can fill pores, replace original material, or create a cast in the surrounding rock. Fossils can also form in amber, volcanic ash, ice, or exceptionally dry environments. The fossil record includes both body fossils and trace fossils.

Fossils are studied by paleontologists, who use them to reconstruct past ecosystems and track evolutionary change. They also help scientists establish the relative ages of rock layers; radiometric dating can provide numerical age estimates. The oldest widely accepted fossils are billions of years old, while the term “fossil” is often applied to remains more than about 10,000 years old. Relics is a general word, and minerals are nonliving substances, so neither is the standard scientific answer.