Question

Which is the evidence to show that $O_2$ released during photosynthesis comes from water?

• A. Synthesis of carbohydrates and formation of $H_{2}O$ and sulphur by photosynthetic bacteria when supplied with $H_{2}S$ and $C{O}_2$
• B. Release of $O_2$ by isolated chloroplasts when potassium ferrocyanide or some other reducing substance is supplied
• C. Release of radioactive $O_2$ when water is supplied as $H_2{O}^{18}$
• D. All the above

Answer 1

Answer: (C)

Release of radioactive $O_2$ when water is supplied as $H_2{O}^{18}$

So, the correct option is 'Release of radioactive O2 when water is supplied as H2O18'.