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15.4: Understanding Earth's History- Challenge 1

  • Page ID
  • 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
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