science

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Across
  1. 4. the end of an organism or of a group of organisms
  2. 8. a vertebrate animal of a class that includes snakes, lizards, crocodiles, turtles, and tortoises.
  3. 10. Any preserved evidence of life from a past geological age
  4. 11. age: The geologic age of a fossil organism, rock, or geologic feature or event defined relative to other organisms, rocks, or features or events rather than in terms of years.
  5. 15. an animal lacking a backbone, such as an arthropod, mollusk, annelid, coelenterate
  6. 17. a scientist who studies fossils.
  7. 19. of superposition: a basic law of geochronology, stating that in any undisturbed sequence of rocks deposited in layers, the youngest layer is on top and the oldest on bottom,
  8. 20. decay: any method of determining the age of earth materials or objects of organic origin based on measurement of either short-lived radioactive elements or the amount of a long-lived radioactive element plus its decay product
  9. 22. the action or process of forcing a body of igneous rock between or through existing formations, without reaching the surface.
  10. 24. Words:
  11. 27. A fossil formed when an animal, plant, or other organism dies and is covered by sediment
  12. 29. The time required for half the quantity of a drug or other substance deposited in a living organism to be metabolized or eliminated by normal biological processes.
Down
  1. 1. the remains or impression of a prehistoric organism preserved in petrified form or as a mold or cast in rock.
  2. 2. a celestial object consisting of a nucleus of ice and dust and, when near the sun, a “tail” of gas and dust particles pointing away from the sun
  3. 3. age: the true age of a rock or fossil
  4. 4. the movement of magma onto the surface of the earth through volcanic craters and cracks in the earth's crust, forming igneous rock.
  5. 5. fossil: a fossil that is useful for dating and correlating the strata in which it is found.
  6. 6. film: fossil found in any rock when organic material is compressed, leaving only a carbon residue or film
  7. 7. a major division of time that is a subdivision of an eon and is itself subdivided into periods.
  8. 9. an animal of a large group distinguished by the possession of a backbone or spinal column, including mammals, birds, reptiles, amphibians, and fishes.
  9. 12. belonging to or characteristic of a past historical time, especially in style or design.
  10. 13. a surface of contact between two groups of unconformable strata.
  11. 14. extinction: a large number of species within a relatively short period of geological time
  12. 16. a warm-blooded vertebrate animal of a class that is distinguished by the possession of hair or fur, the secretion of milk by females for the nourishment of the young, and (typically) the birth of live young.
  13. 18. fossil: a fossil of a footprint, trail, burrow, or other trace of an animal rather than of the animal itself.
  14. 21. A fossil formed when an animal, plant, or other organism dies, its flesh decays and bones deteriorate due to chemical reactions
  15. 23. a crack in a rock along which slippage has occurred.
  16. 25. a cold-blooded vertebrate animal of a class that comprises the frogs, toads, newts, and salamanders.
  17. 26. time scale: a system of chronological dating that relates noah macuha
  18. 28. fossil: a fossil through the replacement of the original material and the filling of the original pore spaces with minerals.