science

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Across
  1. 2. the placement of one thing above or on top of another
  2. 4. The amount of time that it takes one half of the atoms present to decay
  3. 5. the approximate age of a specific rock layer
  4. 6. the preserved remains of plants and animals whose bodies were buried in sediments,
  5. 8. method of age determination that makes use of the radioactive decay
  6. 9. assigning actual dates (in years before the present) to rocks or geological events
Down
  1. 1. a scientific method that can accurately determine the age of organic materials as old as approximately 60,000 years
  2. 3. the extensive interval of time occupied by the geologic history of Earth
  3. 7. the emission of energy in the form of ionizing radiation