Rocks hold secrets to Earth's past. Fossils, which are the preserved remains of life, provide tremendous amounts of information about Earth's history. The fossilization of organisms can occur in a few different ways. Scientists have discovered that if the recently deceased organism is buried quickly it will have a better chance of becoming a fossil. The study of fossils can provide insight to the type of climate, organisms, and conditions that existed at the time when the original organism lived. Even from a fossil like the Mosasaur jaw shown, scientists can infer clues about the life of an organism.