Question

what makes up the backbone of dna?
o sugar and phosphates
o nitrogenous bases and sugar
o a polymer of nitrogenous bases
o nitrogenous bases, sugar, and phosphates

Explanation:

DNA is a double - stranded molecule. Each strand consists of nucleotides. A nucleotide has three components: a nitrogenous base, a sugar (deoxyribose in DNA), and a phosphate group. The backbone of DNA is formed by the sugar - phosphate linkages. The nitrogenous bases are attached to the sugar and are involved in base - pairing (A - T and G - C) which holds the two strands together. So, the backbone is made up of sugar and phosphates.

Answer:

sugar and phosphates