<Tr> <Td> Al </Td> <Td> 8.1 </Td> </Tr> <Tr> <Td> Fe </Td> <Td> 5.0 </Td> </Tr> <Tr> <Td> Ca </Td> <Td> 3.6 </Td> </Tr> <Tr> <Td> Na </Td> <Td> 2.8 </Td> </Tr>

What two layers of the earth are made of rocks