Final answer:
The most abundant elements in living organisms are oxygen and carbon, making up about 96% of their mass. These elements are fundamental to the structure and functioning of all living cells.
Step-by-step explanation:
The most abundant bulk elements that make up the vast majority of living organisms are oxygen (O), carbon (C), hydrogen (H), and nitrogen (N). These elements are crucial because they form the backbone of important biological molecules including nucleic acids, proteins, carbohydrates, and lipids. Together, carbon, hydrogen, nitrogen, and oxygen make up approximately 96% of the mass of living organisms, reflecting the importance of these elements in the structure and function of living cells.
The correct answer to the question is D) Oxygen and Carbon. While elements such as calcium and sodium are important to biological processes, they do not represent the most abundant elements in living organisms compared to carbon and oxygen.