Question: Which of the following structures represents a lipid? Need Assignment Help? A monomer made up of a nitrogenous base, a five carbon sugar, and a phosphate group bonded together. A monomer with an amino group, carboxylic acid, hydrogen atom, and R group bonded to a central carbon atom. A monomer with the formula C6H12O6. Five carbon atoms and one oxygen atom form a hexagonal ring, with the other atoms bonded to that ring. A molecule made up of four carbon rings with other atoms bonded to those rings.