Question

dna is shaped like a twisted ladder. the rungs of the ladder are composed of ____ while the sides of the ladder are composed of ____. multiple choice sugar - nitrogenous bases; phosphate molecules sugar - phosphate molecules; nitrogenous bases phosphate molecules; sugar - nitrogenous bases sugar molecules; phosphate - nitrogenous bases nitrogenous bases; sugar - phosphate molecules

Explanation:

DNA has a double - helix structure. The rungs of the DNA ladder are formed by pairs of nitrogenous bases (adenine - thymine and cytosine - guanine). The sides of the DNA ladder are made up of sugar (deoxyribose) and phosphate molecules, which form the sugar - phosphate backbone.

Answer:

nitrogenous bases; sugar - phosphate molecules