Answer:
D. The number of carbon-carbon double bonds.
Step-by-step explanation:
Linoleic acid is an unsaturated fatty acid with two carbon-carbon double bonds in its hydrocarbon chain. The presence of these double bonds introduces kinks or bends in the molecule, making it less linear and more flexible than saturated fatty acids. The more double bonds a fatty acid has, the more it can twist and bend, resulting in a less rigid structure. The double bonds create "kinks" that prevent the molecules from packing tightly together, a characteristic of saturated fatty acids.