Final answer:
The six critical elements constituting 98% of the mass of living organisms are carbon, hydrogen, nitrogen, oxygen, phosphorus, and sulfur, with oxygen, carbon, hydrogen, and nitrogen accounting for more than 95% of the body's mass.
Step-by-step explanation:
The six critical elements that make up 98% of the mass of organisms are carbon (C), hydrogen (H), nitrogen (N), oxygen (O), phosphorus (P), and sulfur (S). These elements are fundamental building blocks of living matter and are found in the nucleic acids, proteins, carbohydrates, and lipids that comprise all life forms. Biologists recognize these elements as essential because they allow for the formation of cells, tissues, organ systems, and entire organisms.
When discussing the human body, the four elements that make up more than 95 percent of the body's mass specifically are oxygen, carbon, hydrogen, and nitrogen. This also reflects how common elements in the universe such as hydrogen and oxygen (which combine to form water), along with carbon and nitrogen, are not only plentiful but also vital to the chemistry of life.
While oxygen is the most abundant element in the Earth's crust, making up about 47 percent by weight, it is also the most abundant element in the human body by mass. Thus, understanding these elemental compositions helps to elucidate a profound connection between living organisms and the Earth's environment.