#radioactivity_unit__radioactivityunit  a measure of radioactivity
  supertype:  radioactivity_measure (pm)  electromagnetic_unit
  subtype:  millicurie  a unit of radioactivity equal to one thousandth of a curie
  subtype:  curie__Ci  a unit of radioactivity equal to the amount of a radioactive isotope that decays at the rate of 37,000,000,000 disintegrations per second
  subtype:  roentgen__R  a unit of radiation exposure; the dose of ionizing radiation that will produce 1 electrostatic unit of electricity in 1 cc of dry air
  subtype:  rutherford  a unit strength of a radioactive source equal to one million disintegrations per second
  subtype:  REM__rem  (Roentgen Equivalent Man) the dosage of ionizing radiation that will cause the same amount of injury to human tissue as 1 roentgen of X-rays
  subtype:  rad  a unit of absorbed ionizing radiation equal to 100 ergs per gram of irradiated material

1 statement is about a direct instance of radioactivity_unit: graph1_on_radiation
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