Question

what makes up the sides of the \ladder\ of a dna molecule? phosphate

Explanation:

The sides of the DNA "ladder" (the backbone) are made up of alternating sugar (deoxyribose) and phosphate groups. The initial answer "Phosphate" is incomplete as it's part of the backbone along with deoxyribose. So the correct description involves both, but if we consider the components, the backbone has phosphate and sugar. However, if we correct the answer, the sides are formed by sugar - phosphate backbones (alternating deoxyribose and phosphate).

Answer:

The sides of the DNA "ladder" (the backbone) are composed of alternating deoxyribose (sugar) and phosphate groups. So the correct components for the sides include both deoxyribose (sugar) and phosphate, with the backbone being a sugar - phosphate backbone (alternating deoxyribose and phosphate).