What distinguishes polyunsaturated fatty acids?

• A. More than one double bond
• B. One double bond
• C. No double bonds
• D. Three double bonds

Answer: (A)

Polyunsaturated fatty acids are defined by having more than one carbon–carbon double bond in their hydrocarbon chain. That degree of unsaturation sets them apart from saturated fats, which have no double bonds, and from monounsaturated fats, which have exactly one double bond. The exact number of double bonds can vary (two, three, or more), but the defining feature is that there is more than one. These multiple double bonds create kinks in the chain, preventing tight packing and making these fats typically liquid at room temperature, unlike saturated fats. The option stating more than one double bond best captures this distinction.