Final answer:
Cobalt (Co) is not considered a macroelement.
Step-by-step explanation:
The element Cobalt (Co) is not considered a macroelement.
Macroelements are elements that are required in relatively appreciable amounts in the body, such as iron (Fe), sodium (Na), and potassium (K).
Carbon (C), calcium (Ca), and potassium (K) are all considered macroelements.