<Tr> <Td> Nuclear fuel cycle </Td> <Td> 0.0002 </Td> <Td> </Td> <Td> 0.001 </Td> <Td> up to 0.02 mSv near sites; excludes occupational exposure </Td> </Tr> <Tr> <Td> Other </Td> <Td>--</Td> <Td> 0.003 </Td> <Td> </Td> <Td> Industrial, security, medical, educational, and research </Td> </Tr> <Tr> <Td> sub total (artificial) </Td> <Td> 0.61 </Td> <Td> 3.14 </Td> <Td> 2.33 </Td> <Td> </Td> </Tr> <Tr> <Td> Total </Td> <Td> 3.01 </Td> <Td> 6.24 </Td> <Td> 3.83 </Td> <Td> millisieverts per year </Td> </Tr>

Identify three activities that add to background radiation