Why would it be hard to find the ideal co2 level if the light intensity were very low

In photosynthesis, light and CO2 are required in order to perform properly. Thus, if only low levels of light are present, the process of photosynthesizing will produce inaccurate and slow results due to the imbalance of materials the plants is using. The plant should have a balanced amount of CO2, light, and water in order to find the ideal levels of CO2.