Statement A: Rubisco of bundle sheath cells of C4 plants shows more carboxylase activity than the mesophyll cells of C3 plants.Statement B: High CO2 concentration is maintained in bundle sheath cells of C4 plants than in mesophyll cells of the same plant.

The CO2 involved in carboxylation of PEP in mesophyll cells of C4 plants is pumped into bundle sheath cells to maintain high CO2 concentration to avoid or decrease the oxygenase activity of Rubisco. In C3 plants, the CO2 concentration of its green cells is far lower. Hence these plants show relatively more photorespiratory loss of carbon than C4 plants.