Describe how three factors can limit the rate of photosynthesis in a plant.

1. Carbon dioxide concentration – when CO₂ is low, the Calvin cycle cannot fix enough carbon, so the overall rate of photosynthesis is limited.
2. Light intensity – if light is insufficient, the light‑dependent reactions produce fewer ATP and NADPH, limiting the rate.
3. Temperature – enzymes involved in photosynthesis have an optimum temperature; at low or high temperatures their activity drops, so the rate is limited.
Each factor is a limiting factor because it is the one in shortest supply that restricts the overall rate of photosynthesis.