Which of the following is an example of a lipid?

A lipid is a category of biomolecules that are insoluble in water but soluble in nonpolar solvents. They play key roles in cellular structure and function. Fats are one of the most common types of lipids and are crucial for storing energy, as well as forming cell membranes and serving as signaling molecules.

In this case, fat is indeed an example of a lipid because it is composed of fatty acids and glycerol, which are characteristic components of lipid molecules. Other types of lipids include oils and waxes, but fat is the most recognized in the broader context of lipids.

The other options do not fit the category of lipids: starch is a carbohydrate, proteins are made up of amino acids, and vitamin C is a water-soluble vitamin. Understanding the differences in these categories is essential in biology and biochemistry, as it highlights the distinct functions and structures of various biological molecules.