What are the "twisty columns" and "rungs" in the DNA?

The twisty columns of the double helix are phosphate and sugar (deoxyribose), which are bonded by a covalent bond. Each nucleotide consists of one of each, and also a nitrogen base. The rungs are nitrogen bases, each nucleotide has one base, and one side of the ladder bonds to the other side of the ladder through hydrogen bonding of complementary base pairs. The base pairs of DNA are A-T and C-G

Answer: The twisty columns of the double helix are phosphate and sugar (deoxyribose), which are bonded by a covalent bond.