History of Life on Earth

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Across
  1. 6. remains or traces of a once living organism
  2. 7. the study of development of unborn or unhatched organisms
  3. 8. when all members of a species die out
  4. 9. the process of biological change by which populations become different from their ancestors over many generations
Down
  1. 1. the idea that all organisms share a common ancestral species from which they evolved as some point in the past
  2. 2. the body structure of an organism and its structural traits
  3. 3. the history of life on Earth as it is preserved by fossils
  4. 4. a record of the activity of an organism such as footprints, scratches, and fossilized dung
  5. 5. happens when an organism's tissues are replaced by minerals from water