The limiting rate of photosynthesis at the point X is the light intensity. A limiting factor in biology, is a factor that limits a biological process. A photosynthesis is a biological process that the plant uses to convert the light into chemical energy which is released to provide energy to the organisms.
This chemical energy is stored as molecules of carbohydrates in the form of sugars, which are later made from carbon dioxide and water. Oxygen is released as a waste product in this process. It is majorly responsible for producing the oxygen in the earth’s atmosphere.
Limiting factor - factor required in minimum amount. As light intensity increases, the rate of photosynthesis does not continue to increase. Other factors will help to increase the rate of photosynthesis