Question

The purpose of these two investigations was to show gas exchange during photosynthesis. In 3-5 sentences explain why two investigations are needed to show gas exchange during photosynthesis?

Answer 1

Photosynthesis involves two complementary gas changes — carbon dioxide is taken up and oxygen is released — and a single experiment usually detects only one of those changes. Running two different investigations (for example, measuring oxygen bubbles from an aquatic plant and using an indicator or limewater to show CO2 disappearance) provides direct evidence for both processes. Using both tests plus light/dark controls also rules out other explanations such as respiration, which could mask or mimic one gas change. Together the experiments give a complete and reliable demonstration of gas exchange during photosynthesis.