Final answer:
The human body is primarily made up of six major elements: oxygen, carbon, hydrogen, nitrogen, calcium, and phosphorous, which are essential components of biological molecules and account for the majority of the body's composition.
Step-by-step explanation:
About 98% of the human body is composed of a few elements, with oxygen, carbon, hydrogen, nitrogen, calcium, and phosphorous being the most abundant. These are considered major elements because they are required in large quantities for the structure and function of the body. For instance, these elements are vital components of biological molecules such as nucleic acids, proteins, carbohydrates, and lipids.
Hydrogen, oxygen, carbon, and nitrogen collectively account for 96% of living organisms, and they form the fundamental building blocks of life. The human body is able to concentrate these elements, even though some may be rare in Earth's crust, through the consumption of food and water, obtaining elements in assimilable forms for sustaining various biological processes.