Question

Oxygen produced in photosynthesis comes from H${}_2$O was shown by

• A. Robert Mayer
• B. Ruben and Kamen
• C. Calvin
• D. Robert Hill

Answer 1

Answer: (B)

Ruben and Kamen

Ruben and Kamen (1941) through their experiments using heavy water stated that O${}_2$ evolved during photosynthesis comes from water and not CO${}_2$. For the experiment, they used heavy radioisotopes of Oxygen (O${}^{18}$) in water (H${}_2$O${}^{18}$) and CO${}_2$${}^{18}$.

So, the answer is B.