Answer: Single covalent bond in the long hydrocarbon chain.
Saturated fatty acids are long chains of hydrocarbon ( with single covalent bond) ending with the carboxylic group (-COOH). This means those fatty acids which possess only single bonds in their chemical structure are called as saturated fatty acids. They are densely packed, which makes them solid at room temperature.
Example- Lauric acid ( present in coconut oil). It has 12 carbon atoms in its chemical structure.
