Final answer:
Saturated fatty acids have only single bonds in the hydrocarbon chain, while unsaturated fatty acids have at least one double bond. Saturated fatty acids are fully saturated with hydrogen.
Step-by-step explanation:
In a fatty acid chain, saturated fatty acids have only single bonds between neighboring carbons in the hydrocarbon chain, while unsaturated fatty acids have at least one double bond.
An example of a saturated fatty acid is stearic acid (C18H36O2) which has a straight chain, while unsaturated fatty acids have bent chains due to the presence of double bonds.
The number of hydrogen atoms attached to the carbon skeleton of saturated fatty acids is maximized, making them fully saturated with hydrogen.