Final answer:
Elements like carbon, oxygen, and hydrogen are considered macronutrients because they are required by the body in large amounts, making option C the correct answer for elements needed in quantities more than 0.1% of an organism's body weight.
Step-by-step explanation:
Understanding Macronutrients
Elements required by the body in large amounts, such as carbon, oxygen, and hydrogen, are classified as macronutrients. These elements are involved in fundamental biological processes and form the building blocks of carbohydrates, lipids, proteins, and nucleic acids. Macronutrients, including carbon (C), hydrogen (H), nitrogen (N), oxygen (O), phosphorus (P), sulfur (S), and calcium (Ca), are typically needed in quantities that exceed 0.1% of an organism's dry weight. In contrast to micronutrients or trace elements, which are required in much smaller amounts, macronutrients are essential for maintaining the body's structure and function.