C3, C4m and CAM plants

1. C3 plants
These are plants in which CO2 comes directly from the air. In these plants, carbon fixation produces 3 carbon compounds. If it's dry there is no photosynthesis.
Examples: rice, wheat, soybeans
2. C4 plants
Carbon fixed in bundle sheath tissue surrounds the veins. These plants are fixed into four carbon compounds. They're not susceptible to O2. Even at low CO2 levels there is still such thing as fixed carbon. The 4 carbon compounds are in charge of taking CO2 into the Calvin cycle.
Examples: Corn and sugarcane
3. CAM plants
The stomata of these plants only opens at night. They fix caron into 4 carbon compounds(vacuoles) The calvin cycle in these plants happens throughout the day.
Examples: cacti, deserted adapted plants.