${\mathrm{CO}}_2$ saturation point in photosynthesis for ${\mathrm{C}}_3$ plants (A) and ${\mathrm{C}}_4$ plants (B) is 
 

	A	B
1.	360 $\mathrm{\mu L}/\mathrm{L}$	450 $\mathrm{\mu L}/\mathrm{L}$
2.	450 $\mathrm{\mu L}/\mathrm{L}$	360 $\mathrm{\mu L}/\mathrm{L}$
3.	250 $\mathrm{\mu L}/\mathrm{L}$	150 $\mathrm{\mu L}/\mathrm{L}$
4.	360 $\mathrm{\mu L}/\mathrm{L}$	650 $\mathrm{\mu L}/\mathrm{L}$

CO₂ saturation point is higher for C₃ plants than C₄ plants.  C₄ plants show saturation at about 360 µlL^-1 while C₃ responds to increased CO₂ concentration and saturation is seen only beyond 450 µlL^-1.