In what way can dna segments be changed such that genes are altered or mutated? i. new dna segments can be inserted. ii. new dna segments can be substituted. iii. dna segments can be deleted.

That would be I, II, and III 

I and II will cause a frame shift mutations. 
II can cause horrible effects if the substituted base codes for a stop codon. 

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.