How many given matches are correct?(a) Mg – Association of ribosomal sub-units.(b) S – Constituent of biotin and thiamine.(c) Fe – Activates catalase.(d) N – Mineral elements required by plants in the greatest amount.

Iron activates catalase enzyme.Sulphur is the main constituent of several coenzymes, vitamins (thiamine, biotin, Coenzyme A) and ferredoxin.Magnesium is a constituent of the ring structure of chlorophyll and helps to maintain the ribosome structure.Nitrogen is the essential nutrient element required by plants in the greatest amount.