'Photosynthesis is the conversion of light energy within a plant' was first stated by

Two plants $A$ and $B$ are supplied with $CO_2$ with $H_2O^{18}$ and $CO_2^{18}$ with $H_2O$ respectively. Which of the following plants releases $O^{18}$ type oxygen in photosynthesis?

The statement "The amount of $CO_2$ absorbed and $O_2$ released during photosynthesis are in equal volumes" was proved by:

Which scientist performed the experiment where a burning candle and a mouse were placed in a closed bell jar to demonstrate the role of air in the growth of plants?

The essential role of air in the growth of green plants was revealed by

The discovery that the first stable product of $CO_2$ fixation in photosynthesis is $3$-phosphoglyceric acid $(PGA)$ was made by whom?