- (a) Carbon is a macronutrient and an essential component of macromolecules.
- (b) Nitrogen being a macronutrient is a necessary component of nucleic acids and proteins
- (c) Hydrogen is a key component of an inorganic compound including water
- (d) Iron is a macronutrient required for the functioning of cytochromes.
Answer _ (d)
Justification- Iron is a micronutrient that is used to accomplish many biological functions
However as the question suggests iron is an essential component of cytochromes functioning,
this is certainly because cytochromes have central iron (Fe) atom at its core, working as a
cofactor. Though it also suggests iron is a macronutrient, which makes the statement wrong
despite the other part of the option being completely true.