Photosynthesis is underthe influence of several factors, both internal (plant) and external. The plant factors include the number, size, age and orientation of leaves, mesophyll cells and chloroplasts, internal $CO_{2}$ concentration and the amount of chlorophyll. The plant or internal factors are dependent on the genetic predisposition and the growth of the plant. The external factors include the availability of sunlight, temperature, $CO_{2}$ concentration and water. During photosynthesis, all these factors simultaneously affect its rate.