Fossilization
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A fossil is remains of an ancient organism that was once living that is preserved in rock.The discovery of fossils has given scientists information about the Earth before humans existed. Fossils can be found in a variety of sizes and range in age from a few thousand years to hundreds of millions of years old. Even though we tend to think about animal bones being the most common example of a fossil, this is not the case. Paleontologists could also discover plant fossils, bug fossils, implants (foot prints), eggs, nests, etc. Fossils are created in several different ways and classified into the following categories: mold & cast fossils (imprints or impressions), true form fossils (actual organism remains), trace fossils (such as footprints), and carbon film fossils (carbon silhouette left on rock). Most fossils form in sediment (dirt/mud that hardens into rock). It takes many years for an organism to turn into a fossil. Fossils can be found in any rock surface, from mountains to sea beds. Fossils are typically best preserved in sediments beneath water. Fossils on land are less common due to the number of predators and an increased rate of decay (how quickly a living thing breaks down). Predators and increased rate of decay could affect fossil formation because the predators could eat it before it becomes a fossil, or it could decay before it has enough time to become a fossil.