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15.4: Understanding Earth's History- Challenge 1
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- 1. Why are the La Brea Tar Pits in Los Angeles, California, an exception?
- they formed under unusual circumstances
- 2. Hard-shelled marine organisms ___ more often than organisms with soft tissues in exposed environments.
- 3. Amber is ___.
- fossilized tree sap
- 4. When insects fossilize, it is usually in ___.
- 5. A bone dissolves and leaves behind a space in a rock called a ___, which fills with minerals to form a ___in the original shape of the organism.
- mold; cast
- 6. ___ can be used to identify a specific period of time.
- Index fossils
- 7. At the time of the fossilization of coal, the temperature of Antarctica was ___.
- 8. Compared with fossils in younger rocks, fossils in older rocks are ___.
- less similar to modern organisms