Digestion breaks down complex molecules into simpler units that can be absorbed by the body. - Proteins are polymers of amino acids, and digestion breaks them down into individual amino acids. (A - > 4) - Carbohydrates (like starch, disaccharides) are broken down into monosaccharides (simple sugars like glucose, fructose, galactose). (B -> 3) - Nucleic acids (DNA, RNA) are broken down into nucleotides, and further breakdown yields nitrogenous bases, pentose sugars, and phosphate groups. Option 1 lists nitrogenous bases and pentose sugars, which are components resulting from nucleic acid digestion. (C -> 1) - Lipids (fats and oils) are broken down into fatty acids and glycerol. (D -> 2)