The cells in our bodies are made up primarily of which four elements? hydrogen, nitrogen, calcium, and oxygen hydrogen, nitrogen, sodium, and oxygen carbon, hydrogen, oxygen, and nitrogen sodium, potassium, chloride, and calcium

The correct answer is: **Carbon, hydrogen, oxygen, and nitrogen** ### Explanation: The human body is primarily composed of four major elements: 1. **Carbon (C)** - Fundamental building block of all organic molecules. 2. **Hydrogen (H)** - Present in water and organic compounds. 3. **Oxygen (O)** - Essential for respiration and a major component of water. 4. **Nitrogen (N)** - Key component of amino acids and nucleic acids. These four elements make up approximately **96%** of the body's mass. The other elements listed in the options, such as sodium, potassium, chloride, and calcium, are indeed important for various physiological functions but are present in much smaller amounts compared to carbon, hydrogen, oxygen, and nitrogen. ### Final Answer: **carbon, hydrogen, oxygen, and nitrogen**