The backbone of the helix attached to the sugar, in between the Deoxyribose sugar
Explanation:
Two strands of DNA form a twisted ladder-like structure by wrapping around one another. The deoxyribose and phosphate units that make up the backbone of each strand alternate in direction. Adenine (A), cytosine (C), guanine (G), and thymine (G) are the four bases that are joined to each sugar (T).
