Final answer:
The four elements that make up about 96% of living organisms are carbon, oxygen, hydrogen, and nitrogen.
Step-by-step explanation:
The four elements that make up about 96% of living organisms are carbon (C), oxygen (O), hydrogen (H), and nitrogen (N). These elements are found in large quantities in the human body and are major elements. Other elements such as phosphorus (P), sulphur (S), and calcium (Ca) are also found in the human body, but in smaller quantities.