What is the importance if the carbon and nitrogen cycles to ecosystems

Carbon and nitrogen and an important element of living things. Nitrogen is a major component of DNA and amino acids while carbon can be found in almost all biomolecules. These elements, therefore, need to be renewed and recycled as they are utilized by ecosystems that is ever dynamic.  

c

explanation:

the sugar-phosphate backbone forms the structural framework of nucleic acids, including dna and rna. this backbone is composed of alternating sugar and phosphate groups, and defines directionality of the molecule.