Oils contain more unsaturated fatty acids than fats

Steps:

• Fats are solid triglycerides with mostly saturated fatty acids at room temperature.
• Oils are liquid triglycerides with mostly unsaturated fatty acids at room temperature.
• Unsaturated fatty acids have carbon-carbon double bonds that create kinks, reducing molecular packing.
• Thus, oils have higher concentrations of unsaturated fatty acids to maintain liquidity.

Why D is correct:

• Unsaturated fatty acids feature double bonds that lower melting points, defining oils as liquid lipids versus solid fats.

Why the others are wrong:

• A: Saturated fatty acids dominate in fats, making them solid, not oils.
• B: Glycerol forms the backbone of both fats and oils equally.
• C: Monounsaturated fatty acids are present but less abundant than polyunsaturated in many oils.

Final answer: D