Module 13 Crossword

3. the time scale that shows major geological and biological events in Earths history
6. the amount of time required for half of a radioactive isotope to decay
7. Theory that sates that living things come from other living things
10. ______________, idea that life comes from nonlife
13. the explosion that lead to rapid diversification of most major animal groups
14. the smallest units of geologic time
15. a boundary that contains a layer of iridium rich material between rocks of the cretaceous period and the paleogene period
16. theory that explains how eukaryotic cells evolved from prokaryotic cells
17. a unit of geologic time that consists of two or more periods

1. scientist who studies fossils
2. type of dating used to determine the age of rocks by comparing with younger and older rock layers
4. plate __________, a geologic theory that Earth's surface is broken into several huge plates that move on molten rock layers
5. law of ____________ states that younger rock layers are on top of older layers
8. the longest unit of geologic time
9. preserved evidence of an organism
11. type of dating that uses radioactive isotopes to determine the age of rocks
12. divisions of geologic time that consists of two or more epochs