Which type of fat is mostly found in plants, liquid at room temperature, and has a lower hydrogen-to-carbon ratio?

• A. Saturated Fats
• B. Trans Fats
• C. Unsaturated Fats
• D. Polyunsaturated Fats

Answer: (C)

The main idea here is how double bonds in fat chains affect both structure and state. Unsaturated fats have one or more double bonds between carbon atoms in their hydrocarbon chains. Those double bonds create kinks, so the molecules don’t stack tightly. That looser packing lowers the melting point, so these fats are liquid at room temperature—just what you’d expect from many plant oils like olive or canola oil. The double bonds also mean there are fewer hydrogens bonded to the carbon chain overall, giving a lower hydrogen-to-carbon ratio compared with fats that are fully saturated. While polyunsaturated fats are a subset with multiple double bonds, the broad category that fits all the clues—found mainly in plants, liquid at room temperature, and having a lower H/C ratio—is unsaturated fats.