Individual #Precambrian_period__Precambrian  the geological era before about 544 million years ago
  instance of:  #geological_era
  part:  #Proterozoic__Preoterozoic_era  from 2,500 to 544 million years ago; bacteria and fungi; primitive multicellular organisms
  part:  #Archean_era__Archean__Archeozoic__Archaeozoic__Archeozoic_era__Archaeozoic_era  the time prior to 2,500 million years ago; earth's crust formed; unicellular organisms are earliest forms of life

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