Select the mismatch
Calcium- Helps in formation of mitotic spindle.
Magnesium - Constituent of the ring structure of chlorophyll.
Copper- Helps in pollen germination.
Molybdenum- Component of nitrate reductase
Boron helps in pollen germination. Copper is associated with certain enzymes involved in redox reactions and is reversibly oxidised from Cu+ to Cu2+.