what reactant are needed for photosynthesis
Best Answer: The equation for photosynthesis is: 6 H2O + 6 CO2 ---> C6H12O6 + 6 O2. Water + Carbon Dioxide yield Glucose + Oxygen. The reactans are on the left, and products are on the right. (Keep in mind that this is not the general equation, but an introductory equation, so it depends what level science you are taking.)