Final answer:
Carbohydrates, lipids, and proteins share three main elements: carbon (C), hydrogen (H), and oxygen (O), and they play key roles in providing energy, building cellular structures, and regulating body processes.
Step-by-step explanation:
The three main elements that carbohydrates, lipids, and proteins share are carbon (C), hydrogen (H), and oxygen (O). These elements are essential building blocks for the macromolecules that make up living organisms. Carbohydrates, often including sugars like glucose, serve primarily as a source of energy and are sometimes stored in complex forms such as starch.
Lipids, which encompass fats and oils, provide long-term energy storage and make up cell membranes. Proteins, made up of amino acids found in foods like meats and nuts, are crucial for building and repairing tissues and regulating body processes.