| A | B |
|---|
| Remains of once-living things that have been preserved. | fossils |
| Imprint left by the outside of a plant or animal. | mold |
| Fossils that show how long-dead animals changed their environments. | trace fossils |
| Minerals that fill a mold and have the same shape as the original living thing. | cast |
| Any fuel formed from the remains of once-living organisms. | fossil fuel |
| Fuel that is mainly used in transportation. | petroleum |
| Type of coal most often used in factories. | bituminous coal |
| Type of coal that produces very little heat. | lignite |
| Early form of coal made up of dead swamp lants. | peat |
| Valuable form of coal that produces a lot of heat and very little smoke. | anthracite |
| Gas fuel used for cooking and heating. | natural gas |
