Answer:
The correct answer would be Carbon dioxide comes from the air and is broken down in the Calvin cycle.
Photosynthesis can be divided into two steps namely light-dependent and light-independent reactions.
In light-dependent reaction, light energy of the sun is converted into chemical energy (ATP and NADPH). Photolysis of water takes place in this process which releases oxygen as the byproduct.
In light-independent reaction (also called as Calvin cycle), carbon-dioxide obtained from air is broken down and rearrange to fix carbon in the form of glucose. The reaction is catalyzed by the enzyme RuBisCO.
