Question

a repeating pattern of sugar-phosphate-sugar-phosphate
choose an answer
1 sugar-phosphate backbone
2 double helix
3 nitrogenous base
4 base pairing

Explanation:

The sugar - phosphate backbone forms the structural framework of nucleic acids (like DNA and RNA). It consists of alternating sugar (deoxyribose in DNA, ribose in RNA) and phosphate groups. The description "a repeating pattern of sugar - phosphate - sugar - phosphate" directly refers to this structure. The double helix is the overall 3D shape of DNA (formed by two strands), nitrogenous bases are the A, T, C, G (in DNA) that pair up (base pairing) within the helix. Since the question is about the repeating sugar - phosphate pattern, it's the sugar - phosphate backbone.

Answer:

1. Sugar - Phosphate Backbone