What is one of the main functions of carbohydrates in living organisms?

Carbohydrates play a critical role in the metabolism of living organisms primarily by acting as key energy sources. They are organic molecules made up of carbon, hydrogen, and oxygen, and they are easily broken down by the body to release energy. This energy is essential for a variety of biological processes, including cellular respiration, where glucose, a simple carbohydrate, is converted into ATP, the energy currency of the cell.

In addition to their role as energy sources, carbohydrates also play structural roles in some organisms—as seen in cellulose in plant cell walls—but their predominant function across a wide range of living organisms is indeed to provide readily available energy. Hence, the statement that carbohydrates act primarily as energy sources accurately reflects their main biological function.