1. Oxygen (O): About 65% of the body's mass is oxygen, primarily found in water (H₂O).
2. Carbon (C): The backbone of all organic molecules, including carbohydrates, lipids, proteins, and nucleic acids. It makes up about 18.5% of the body's mass.
3. Hydrogen (H): Also a major component of water, it accounts for about 9.5% of the body's mass.
4. Nitrogen (N): Found in proteins, nucleic acids (DNA and RNA), and other important compounds. It makes up about 3.2% of the body's mass.
5. Calcium (Ca): Essential for bones and teeth, muscle contraction, nerve function, and blood clotting. It makes up about 1.5% of the body's mass.
6. Phosphorus (P): Important for energy storage, bone formation, and cell signaling. It makes up about 1% of the body's mass.
