Which of the following correctly describes the structure of dna?
group of answer choices

strands of phosphate - nitrogen backbone, with complementary nitrogenous base pairs bound into a double helix

strands of phosphate - sugar backbone, with complementary nitrogenous base pairs bound into a single helix

strands of sugar-nitrogen backbone, with complementary deoxyribose base pairs bound into a double helix

strands of phosphate - sugar backbone, with complementary nitrogenous base pairs bound into a double helix