Which term describes energy-rich organic compounds made from carbon, oxygen, and hydrogen?

• A. Carbohydrate
• B. Fatty Acid
• C. Cholesterol
• D. Lipid

Answer: (D)

Lipids are energy-rich organic compounds built mainly from carbon and hydrogen, with some oxygen. Their long hydrocarbon chains store a lot of energy, which is released when the bonds are broken during metabolism. They’re also hydrophobic, meaning they don’t mix with water, which helps with long-term energy storage without pulling in extra water weight.

While carbohydrates also provide energy and are composed of carbon, hydrogen, and oxygen, they are generally more soluble in water and are used for quicker, readily available energy. Fatty acids are specific components of lipids, and cholesterol is one particular lipid molecule, not the broad category itself. Therefore, the term that best fits “energy-rich organic compounds made from carbon, oxygen, and hydrogen” is lipid.