Question

in this equation for photosynthesis where does the first reactant come from and what happens to it in the photosynthetic process?

6CO2 + 6H2O ---> C6H12O6 + 6O2

A - Carbon Dioxide comes from the air and is broke down in the Calvin Cycle.

B - Water is split to drive NADP to NADPH conversion, which is formed in the Calvin Cycle.

C - Oxygen is released as a gas after water is split.

D - Glucose is formed right after the Calvin Cycle

Answer 1

A stands out most to me, CO comes from the air and air is basically oxygen we breath. When we exhale CO comes out (of course). I would say A is correct. 

Answer 2

Answer:

The correct answer would be A - Carbon Dioxide comes from the air and is broken down in the Calvin Cycle.

In the photosynthetic reaction, 6CO₂ + 6H₂O → C₆H₁₂O₆ + 6O₂, the first reactant is carbon dioxide (CO₂).

It is obtained from the air with the help of gaseous exchange through stomatal pores.  

It is broken down in the Calvin cycle with the help of RuBisCO enzyme.

The carbon obtained from carbon dioxide is fixed to synthesize sugar or glucose.

It takes place in the stroma of the chloroplast.