What are lipids primarily composed of?

Lipids are primarily composed of carbon, hydrogen, and oxygen, which is why the choice highlighting these elements is the correct answer. This composition allows lipids to function effectively in various biological roles. Their structure typically includes long hydrocarbon chains or rings, which can store energy efficiently due to the high energy content of the carbon-hydrogen bonds.

While other elements like nitrogen and sulfur can be found in certain complex lipids or derivatives—such as phospholipids and sphingolipids—the essential building blocks of most lipids do not include these elements at their core. Thus, the focus on carbon, hydrogen, and oxygen in lipids accurately reflects their basic metabolic and structural properties in biological systems.