The fossil record also shows that groups of organisms have changed over time.10. Geologists can use index fossils to matchup rock layers at locations that are far apart.5.b 6.h 7.
The fossil record provides evidence that many different organisms have existed at different times. The fossil might be able to be used as an indexfossil.
Geologists subdivide eras into periods and periods into epochs.6.
Ice ages occurred, as thick continental glaciers advanced and retreated over parts of Europe and North America.17.
They are in-depth studies, as one would expect for the results of a research project that challenges radiometric dating.