| A | B |
|---|
| remains of once -living organisms | fossils |
| time required for half the quantity of a radioactive material to decay | half-life |
| theory explaining that large pieces of the lithosphere are in constant motion | Theory of Plate Tectonics |
| process of a radioactive isotope breaking down until it is stable | radioactive decay |
| scientific study of the origin, physical history, and structure/processes of the Earth | Geology |
| person who came up with the idea of Continental Drift | Wegener |
| age of rocks compared to others | relative age |
| actual age of rocks, how long it's been since formed | absolute age |
