| A | B |
|---|
| infancy | the first stage of the human lifecycle |
| mold | an organisms imprint that is the same size and shape |
| cast | fossil formed by the filling of a mold fossil |
| petrified | replaccement of tissues by minerals which turn to stone |
| organelle | stucture found in the cytoplasm of cells |
| mutation | change in the DNA of a gene |
| fossil record | fossils in sedimentry rock that tell the hisory of the earth |
| evolution | process of change over time |
| shield | a region of Precambriian rock |
| adaptation | a trait that helps a species survive |
