Fat molecules as esters of fatty acids

Steps:

• Fats are triglycerides, formed by esterification of glycerol with three fatty acids.
• The diagram likely shows a glycerol backbone linked to saturated fatty acid chains via ester bonds.
• Saturated fatty acids lack carbon-carbon double bonds, distinguishing them from unsaturated ones.
• The overall structure is an ester, not a free acid.

Why B is correct:

• Triglycerides are esters by definition, where the -COOH groups of saturated fatty acids react with glycerol's -OH groups to form -COO- linkages without double bonds.

Why the others are wrong:

• A: It's an ester, not a free carboxylic acid (which has -COOH).
• C: No double bonds present, so not unsaturated.
• D: Lacks unsaturation (double bonds) in the chains.

Final answer: B