1. Oxygen (O): The most abundant element in living organisms, making up about 65% of body mass. It is a key component of water, carbohydrates, fats, and proteins.
2. Carbon (C): The backbone of organic molecules. It forms the basic structure of carbohydrates, fats, proteins, and nucleic acids. Carbon makes up about 18% of body mass.
3. Hydrogen (H): The simplest element, it is also very abundant in living organisms. It is part of water, carbohydrates, fats, proteins, and nucleic acids. Hydrogen makes up around 10% of body mass.
4. Nitrogen (N): A major component of proteins and nucleic acids (DNA and RNA). It comprises about 3% of body mass.
While these four elements are the most prevalent, other elements are also essential for life, though in smaller amounts. These include calcium, phosphorus, potassium, sulfur, sodium, chlorine, magnesium, and iron.
