which of the structures below represents a fat?

Brief Explanations:

Fats are triglycerides, composed of a glycerol molecule bonded to three fatty - acid chains. The third structure shows a glycerol backbone with three fatty - acid chains attached via ester bonds, which is characteristic of a fat. The first structure is a nucleotide (sugar - phosphate backbone with a nitrogenous base), the second is a steroid (characteristic four - ring structure), and the fourth is a polysaccharide (a chain of monosaccharides).

Answer:

The third structure