Chemical reaction equation such as the one for photosynthesis show the reactants and products of a reaction how does this symbol percolation mystery present what takes place during the process of photosynthesis

The reaction of C02 with water(H20) to give as reactants,to give Oxygen as byproducts and CHO as the chief product is called photosynthesis.

This is usually represented as a single step reaction as

             12C02 +  6H20 + photons of lights → 6C6H12O6 + H20 + 6O2

Explanation:

Far from being true the above equation did not represent the actual course of reaction  taking place.The reaction actually take place in two pathways based on the period of the day.

The first step is Photolysis of water,which refers to the splitting of water molecules to H+ and e- and Oxygen.

H20→ H+ +  4e- +02. .The oxygen from the photolysis reaction  is the oxygen present in the single overall equation above.Because this occur in the day it is called light dependent stage.

Furthermore the  H+ ions is transferred to the second stage of photosynthesis,It takes place in the dark,and therefore called light independent reaction/stage.The hydrogen ion is transferred to the Calvin cycle for the reduction of CO2,to form CHO,protein and Lipids

The essential process involves the chemiosmosis, for ATP synhesis. That is the transfer of the H+ into the thylakoid membrane of the chloroplast,which leads to the build up of hydrogen ions between the thylakoid space, and the set up of elcetochemical gradients.The latter generate energy as Protons diffuses back into the stoma for phophosphorylation of ADP to form ATP by ATPase synthase.

The ATP synthesized is used in Calvin Cycle for carbohydrate synthesis.This is the carbohydrate in the single reaction  of photosynthesis above.

Therefore the single common equation does not give a true reflection of the entire sequence of reaction

the answer is:

carbon dioxide