Question

covalent bonds, weak hydrogen bonds can be easily broken.
complete the paragraph.
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:

• The backbone of DNA is formed by strong covalent bonds between phosphate groups and deoxyribose sugars.
• The rungs of the DNA ladder (the base - pairs) are held together by weak hydrogen bonds between the nitrogenous bases.

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.