Which biomolecule group includes steroids, fats, oils, and waxes?

• A. Proteins
• B. Carbohydrates
• C. Lipids
• D. Nucleic acids

Answer: (C)

Lipids are a broad group of biomolecules that share two key features: they are nonpolar and largely insoluble in water. This family includes fats and oils (triglycerides), waxes, and steroids. Fats and oils store energy for the long term, waxes provide protective waterproofing, and steroids (like cholesterol and steroid hormones) serve signaling and structural roles. In contrast, proteins, carbohydrates, and nucleic acids are built from different monomers and have distinct functions—proteins do work in cells, carbohydrates provide quick energy and structural support, and nucleic acids store and transmit genetic information. The common, nonpolar nature and varied roles within the lipid group make fats, oils, waxes, and steroids fit together under lipids.