<Tr> <Td> C8 group </Td> <Td> - CH CH </Td> <Td> - CH CH </Td> <Td> - CH CH </Td> <Td> - CH = CH </Td> <Td> - CH CH </Td> <Td> - CH CH </Td> </Tr> <Tr> <Td> C17 group </Td> <Td> - CH CH COO - Phytyl </Td> <Td> - CH CH COO - Phytyl </Td> <Td> - CH = CHCOOH </Td> <Td> - CH = CHCOOH </Td> <Td> - CH CH COO - Phytyl </Td> <Td> - CH CH COO - Phytyl </Td> </Tr> <Tr> <Td> C17 - C18 bond </Td> <Td> Single (chlorin) </Td> <Td> Single (chlorin) </Td> <Td> Double (porphyrin) </Td> <Td> Double (porphyrin) </Td> <Td> Single (chlorin) </Td> <Td> Single (chlorin) </Td> </Tr> <Tr> <Td> Occurrence </Td> <Td> Universal </Td> <Td> Mostly plants </Td> <Td> Various algae </Td> <Td> Various algae </Td> <Td> Cyanobacteria </Td> <Td> Cyanobacteria </Td> </Tr>

Which element is found in molecule of chlorophyll