Final answer:
The chemical composition of normal hair is 50% carbon. Carbon is a major component in the composition of a cell and is necessary for all macromolecules.
Step-by-step explanation:
The chemical composition of normal hair is 50% carbon.
Carbon represents 12 percent of the total dry weight of a typical cell and is a component of all macromolecules.
Carbon is necessary and is a major component in the composition of a cell.