Which macronutrient(s) provide(s) cellular energy when metabolized?

• A. Water and minerals provide the most usable cellular energy through direct oxidation
• B. Only proteins provide cellular energy because they are the primary fuel
• C. Only vitamins provide energy because they are coenzymes in metabolism
• D. Carbohydrates, lipids (fats), and proteins all provide energy when metabolized

Answer: (D)