Science

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Across
  1. 1. Supercontinent that existed during the late Paleozoic and early Mesozoic eras
  2. 4. the smallest unit of ordinary matter that forms a chemical element.
  3. 5. The movement of magma onto the surface of the earth through volcano craters and cracks in the earth's crust, forming igneous rock.
  4. 7. A supercontinent that existed during the late Paleozoic and early Mesozoic eras.
  5. 8. The time taken for the radioactivity of a specified isotope to fall to half its original value.
  6. 10. a group of extinct marine mollusc animals in the subclass Ammonoidea of the class Cephalopoda.
  7. 14. A warm-blooded vertebrate animal of a class that is distinguished by the possession of hair or fur
  8. 15. animal without a backbone
  9. 17. a major division of time that is a subdivision of an eon and is itself subdivided into periods.
  10. 18. A break in the Earth's crust
  11. 19. Having no living members; no longer in existence
  12. 22. History of life as documented by fossils
  13. 23. An explanation of an aspect of the natural world and universe that has been repeatedly tested and corroborated in accordance with the scientific method, using accepted protocols of observation, measurement, and evaluation of results.
  14. 24. 3.5 bya
  15. 25. 260 mya
  16. 26. an animal of a large group distinguished by the possession of a backbone or spinal column, including mammals, birds, reptiles, amphibians, and fishes.
Down
  1. 2. Studies the changes in the Earth's rocks
  2. 3. The gradual movement of the continents across the earth's surface through geological time.
  3. 6. 65 mya
  4. 9. The placement of one thing above or on top of another The principle used to determine whether one sedimentary rock is older than another
  5. 11. Any animal or plant preserved in the rock record of the Earth that is characteristic of a particular span of geologic time or environment
  6. 12. Studies the history of life on Earth
  7. 13. A body of igneous (created under intense heat) rock that has crystallized from molten magma.
  8. 16. 4.6 bya
  9. 20. a pure substance consisting only of atoms that all have the same numbers of protons in their nuclei.
  10. 21. 225 mya