1. Oxygen (O): A major component of water, essential for respiration and many metabolic processes.

2. Carbon (C): The backbone of all organic molecules, including carbohydrates, lipids, proteins, and nucleic acids.

3. Hydrogen (H): Found in water and many organic molecules, involved in energy production and cellular processes.

4. Nitrogen (N): A component of proteins, nucleic acids, and other essential molecules.

5. Calcium (Ca): Important for bone and teeth formation, muscle contraction, and nerve function.

6. Phosphorus (P): Part of nucleic acids, ATP (energy carrier), and phospholipids (cell membranes).

7. Potassium (K): Essential for nerve impulses, muscle function, and maintaining fluid balance.