Answer:
The correct answer is - carboxyl group.
Explanation:
Lipids are one of the major macromolecules that are made up of fatty acid and carboxyl groups as two main parts of the molecules. The most common type of lipid is formed with the glycerol associated with the fatty acid chain.
In the provided structure the circled part is the carboxyl group with the long fatty acid chain. However, glycerol belongs to the alcohol group.
Thus, the correct answer is - carboxyl group.
