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Grade 4 C-2 Sci. Def
Chapter 2 Fossils
Term | Definition |
---|---|
Fossil | A preserved clue to life on Earth long ago |
Trace fossil | A fossil that shows changes that long-dead animals made in their surroundings |
Mold (fossil) | A fossil imprint made by the outside of a dead plant or animal |
Cast | A fossil formed when sediments or minerals fill a mold; it takes on the same outside shape as the living thing that shaped the mold |
Fossil fuel | Fuel formed from the remains of organisms that lived long ago |
Petroleum | A thick brown or black liquid fossil fuel; crude oil |
Natural gas | A gas, mostly methane, usually found with petroleum |
Peat | A soft, brown material made up of partly decayed plants; first stage of coal formation |
Lignite | A soft, brown rock; the second stage of coal formation |
Bituminous coal | A fairly hard, dark brown or black rock; third stage of coal formation |
Anthracite | A hard, black rock; fourth stage of coal formation |