Which gas may become deficient in a greenhouse and might need to be pumped in?

In a greenhouse environment, carbon dioxide (CO2) is essential for the process of photosynthesis, which plants use to convert light energy into chemical energy. During the day, plants absorb CO2 from the air, and if the levels of this gas become deficient, plant growth and health can be adversely affected.

In a closed environment like a greenhouse, especially one that is well-sealed, the CO2 levels can drop significantly as plants utilize it. To maintain optimal growing conditions and support robust plant development, growers often need to monitor and, if necessary, supplement the levels of carbon dioxide. This ensures that plants have enough of this critical resource for photosynthesis, directly impacting their growth rate and productivity.

Oxygen is typically not a limiting factor in greenhouses since it is a natural component of air. Nitrogen and argon, while present in the atmosphere, do not play a direct role in the photosynthetic process in the same way that carbon dioxide does. Therefore, the need to pump in additional carbon dioxide to sustain plant growth makes it the correct answer to this question.