Question

what is/are the variable structure(s) in dna and rna nucleotides?
the phosphate group
the sugar and the base
the sugar
the base

Explanation:

Nucleotides (DNA and RNA) have three components: phosphate group, sugar, and nitrogenous base. The phosphate group is identical in both. The sugar differs (deoxyribose in DNA, ribose in RNA). Additionally, the nitrogenous bases vary: DNA uses A, T, C, G; RNA uses A, U, C, G. Both sugar and base are variable between DNA and RNA nucleotides.

Answer:

the sugar and the base