Question

complete the paragraph.
strong hydrogen nitrogenous bases weak covalent
weak hydrogen strong covalent deoxyribose sugars
the structure of a dna molecule resembles a twisted ladder. the sides of the ladder, or
the backbones of the molecule, are formed by bonds between the
phosphate groups and the. the rungs of the ladder are formed by
bonds between the.

Explanation:

• DNA backbone: Strong covalent bonds link phosphate groups and deoxyribose sugars.
• DNA rungs: Weak hydrogen bonds connect nitrogenous bases (A - T, G - C).

Answer:

The sides of the ladder, or the backbones of the molecule, are formed by strong covalent bonds between the phosphate groups and the deoxyribose sugars. The rungs of the ladder are formed by weak hydrogen bonds between the nitrogenous bases.