What is the importance of the carbon and nitrogen cycles to ecosystems? they are needed to release the energy stored in food. they provide materials organisms need to build their bodies. they ensure that matter only moves within a nonliving environment. they supply the energy needed for living processes.

I believe it's number 2

The higher you go up the less oxygen there is 

The main role of dna in the  cell is the long-term storage of information. it is often compared to a blueprint, since it contains the instructions to construct other components of the  cell, such as  proteins  and rna molecules.the main function of rna is to carry information of amino acid sequence from the genes to where  proteins  are assembled on  ribosomes  in the  cytoplasm. mark brainliest, my work is good.