In photosynthesis, the source of O2 released into the atmosphere is:

Question

Accepted Answer

C. H2O (via photolysis in PS II)

**WATER is split (photolysis) by PSII:** 2H2O → 4H+ + O2 + 4e⁻.
This is the source of atmospheric O2 (proved by Ruben + Kamen using ¹⁸O isotope). NOT from CO2.

Answer

CO2 (the carbon dioxide molecule)

Answer

Glucose (from carbon fixation)

Answer

Ozone (O3) in the upper atmosphere

In photosynthesis, the source of O2 released into the atmosphere is:

Keep practising Photosynthesis in Higher Plants