Across
- 3. earth's crust forms
- 5. Life multiplies and radiates, largest proliferation in earth's history
- 8. Earth's oxygen forms for the first time
- 9. modern humans/agriculture appears
- 10. a period that is divided into two shorter periods where hominids appear
Down
- 1. most oxygen in earth's history
- 2. largest extinction of the 5
- 4. jawless fish
- 5. this period ended the dinosaurs by a meteor strike
- 6. age of dinosaurs
- 7. eon where multicellular organisms appear