Evolution

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Across
  1. 2. this type of selection occurs without human interference
  2. 4. an organisms ability to reproduce
  3. 6. preserved remains of organisms
  4. 7. the rate it takes a radioactive sample to decay to half its original mass
  5. 8. the Galapagos islands are an example of this type of isolation
  6. 9. a physical or behavioral change to help an organism survive better
Down
  1. 1. change over a period of time
  2. 3. these type of organ is known as "useless"
  3. 5. estimated age of ground layers (2 words)
  4. 9. this type of selection is done by humans