Final answer:
Carbon is the essential macronutrient found in the macromolecules of humans and other organisms.
Step-by-step explanation:
The essential macronutrient found in the macromolecules of humans and other organisms is carbon.
Carbon is necessary and is a major component of all macromolecules, including carbohydrates, proteins, nucleic acids, lipids, and many other compounds. It accounts for about 50% of the total composition of a cell.