Final answer:
Lipids are a class of macromolecules that are formed from fatty acids.
Step-by-step explanation:
Lipids are a class of macromolecules that are nonpolar and hydrophobic in nature. They are formed from fatty acids. Fatty acids are carboxylic acids with 12-22 carbon atoms connected in a long, unbranched chain. Most lipids, such as fats and oils, are esters or amides of fatty acids.