| A | B |
|---|
| geology | the study of fossils |
| geologic time scale | an outline of Earth's history |
| era | largest division of time |
| Big Bang Theory | theory on the creation of the universe |
| theory | ideas supported by evidence |
| law | theory proven by exact evidence and retested |
| Pangea | all continents combined |
| fossils | a record of past life in form of a track or a trace |
| index fossils | used to date the rock layer they are found in |
| trilobite | Paleozoic |
| ammonite | mesozoic |
| extinct | gone |
| relative dating | giving a date unknown for sure |
| radiometric dating | a technique that uses radioactivity to find ages |
| half-life | the amount of time needed for 1/2 of the atoms to decay |
