Identifying the correct polymer statement

Steps:

• Examine linkages in fats (ester, -COO-) and nylons (amide, -CONH-); neither is solely -O-.
• Review condensation polymerization: requires bifunctional monomers, but not always both -COOH and -OH in one (e.g., diacid + diol).
• Test polythene's reactivity: saturated hydrocarbon chain, no unsaturation to decolorize Br2 without catalyst.
• Verify proteins: amide (-CONH-) bonds hydrolyze easily, enabling biodegradation.

Why D is correct:

• Proteins feature peptide bonds (-CONH- linkage), which undergo hydrolysis to break into amino acids, confirming biodegradability per biochemical definitions.

Why the others are wrong:

• A: Fats have ester (-COO-) and nylons amide (-CONH-) linkages, not -O-.
• B: Condensation monomers can be separate, like dicarboxylic acid and diamine for nylons.
• C: Polythene is saturated, inert to Br2 decolorization without UV initiation.

Final answer: D