<Tr> <Td> 45 </Td> <Td> 68 </Td> <Td> erbium </Td> <Td> Er </Td> <Td> </Td> <Td> 3.8 </Td> <Td> 3.0 </Td> <Td> </Td> <Td> 3.5 </Td> <Td> </Td> </Tr> <Tr> <Td> 46 </Td> <Td> 70 </Td> <Td> ytterbium </Td> <Td> Yb </Td> <Td> </Td> <Td> 3.3 </Td> <Td> 2.8 </Td> <Td> </Td> <Td> 3.2 </Td> <Td> </Td> </Tr> <Tr> <Td> 47 </Td> <Td> 55 </Td> <Td> caesium </Td> <Td> Cs </Td> <Td> </Td> <Td> </Td> <Td> 1.9 </Td> <Td> </Td> <Td> </Td> <Td> </Td> </Tr> <Tr> <Td> 48 </Td> <Td> </Td> <Td> beryllium </Td> <Td> Be </Td> <Td> </Td> <Td> 2.6 </Td> <Td> 1.9 </Td> <Td> </Td> <Td> 2.8 </Td> <Td> 220 </Td> </Tr>

What are the five most abundant elements on earth