Here's why:

* Fatty Acid Structure: Oleic acid is a monounsaturated fatty acid, meaning it has one double bond in its hydrocarbon chain. This double bond introduces a kink into the molecule, making it less likely to pack tightly together.

* Melting Point: The melting point of oleic acid is 13.4°C (56.1°F). Since room temperature is typically around 20-25°C (68-77°F), oleic acid would be a liquid at room temperature.

Note: The exact temperature at which oleic acid becomes a liquid can vary slightly depending on factors like purity and pressure.