<Tr> <Td> Building blocks (number) </Td> <Td> </Td> <Td> </Td> <Td> 20 </Td> </Tr> <Tr> <Td> Strandedness </Td> <Td> Double </Td> <Td> Single </Td> <Td> Single </Td> </Tr> <Tr> <Td> Structure </Td> <Td> Double helix </Td> <Td> Complex </Td> <Td> Complex </Td> </Tr> <Tr> <Td> Stability to degradation </Td> <Td> High </Td> <Td> Variable </Td> <Td> Variable </Td> </Tr>

What type of macro molecule is an enzyme