Which statement describes polyunsaturated fatty acids?

• A. They have more than one double bond and are typically liquid at room temperature
• B. They have no double bonds
• C. They are always solid at room temperature
• D. They are monounsaturated

Answer: (B)

Polyunsaturated fatty acids have more than one double bond in their carbon chain. Each double bond creates a bend, which prevents the fatty acids from packing tightly together. That looser packing lowers the melting point, so these fats are typically liquid at room temperature. The statement describing no double bonds would apply to saturated fats, which can be solid at room temperature because they pack tightly. Monounsaturated fats have one double bond, while polyunsaturated fats have two or more, which is what makes them distinct.