Prehistoric Giants

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Across
  1. 1. a period in Earth's history where ice-sheets covered land
  2. 2. animals that eat only plants
  3. 3. time before recorded or written history
  4. 4. no longer in existence; completely wiped out
  5. 6. the natural environment of plant and animals
  6. 7. a group of living things that are similar and reproduce
Down
  1. 1. animals that don't have a backbones
  2. 4. large divisions of time in Earth's history
  3. 5. long, flexible limbs like on a invertebrate