1. Carbohydrates: These are made up of carbon, hydrogen, and oxygen. They are the primary source of energy for living organisms. Examples include sugars, starches, and cellulose.

2. Lipids (Fats and Oils): These are also made up of carbon, hydrogen, and oxygen, but with a higher proportion of hydrogen. They serve as long-term energy storage, insulation, and structural components of cell membranes. Examples include fats, oils, and waxes.

3. Proteins: These are complex molecules made up of amino acids. They perform a vast array of functions in living organisms, including structural support, enzymatic activity, transport, and immune defense. Examples include enzymes, antibodies, and collagen.

4. Nucleic Acids: These are complex molecules made up of nucleotides. They carry genetic information and are responsible for the transmission of hereditary traits. Examples include DNA and RNA.