Answer:
An increase in the carbon dioxide concentration increases the rate at which carbon is incorporated into carbohydrate in the light-independent reaction - and so the rate of photosynthesis generally increases until limited by another factor.
Step-by-step explanation:
CO2 concentration is directly proportional to rate of photosynthesis.
CO2 is raw material for process of photosynthesis.
CO2 + H2O → C6H12O6 + O2
Increase in CO2 concentration increases rate of photosynthesis.
Decrease in CO2 concentration decreases rate of photosynthesis.
Therefore, CO2 concentration is limiting factor for rate of photosynthesis.