Question

why germinating seeds are used for the experiment??​

Answer 1

because they continuously respiring and liberating co2 that is absorbed in koh

solution used in the experiment

Answer 2

Green leaves cannot be used as the carbon dioxide liberated by them is again reabsorbed by them by photosynthesis. Hence we can't detect the presence of CO2

But germinating seeds do not perform photosynthesis hence we can detect they CO2 is liberated during respiration.