The C4 plants are plants that are able to sustain very harsh conditions, namely the hot and dry conditions. The reason for that is that these plants cycle the carbon dioxide into four carbon sugar compounds to enter the Calvin system. These plants, in this manner, manage to produce a lot of energy which is crucial for their survival in the harsh dry and hot conditions. The cactus, acacia, sugar cane, corn, are examples of this type of plants.
The C3 plants on the other hand are not able to produce energy in the same manner as the C4 plants, thus they need much more moderate weather conditions to survive. They take in the carbon dioxide through the minuscule pores of the leaves. After that the enzyme Ru BisCO helps the carbon dioxide to combine with the sugars, and only than the carbon dioxide and the sugar form a molecule with three carbon atoms in the chloroplast. The tomatoes, cucumbers, apples, plums, are example of this type of plants.
