Biological molecule classifications Steps:

• Review options for logical relationships: position 1 as specific molecule, 2 as category, 3 as related subunit, 4 as building block type, 5 as contrasting molecule.
• Eliminate options with mismatched categories (e.g., enzymes with polymers, proteins with carbs).
• Confirm C aligns with sugar chemistry: fructose and β-glucose as monosaccharides.
• Verify no cross-class errors like including amino acids in carb diagrams.

Why C is correct:

• Fructose is a monosaccharide reducing sugar derived from glucose isomers, with β-glucose as its monomer form and amino acid as a non-carb monomer, matching biochemical definitions of sugar structures.

Why the others are wrong:

• A: Amylase (enzyme) unrelated to cellulose-starch polymer-monomer chain.
• B: Amylase not a carbohydrate, breaking the carb-focused sequence.
• D: Amylase (enzyme) not a protein like haemoglobin; cellulose unrelated to proteins.

Final answer: C