I believe the answer is 3-PGA, ( 3-Phosphoglycerate).Photosynthesis is the process by which plants make their own food using energy from sunlight and takes place in the leaves of plants in the organelle called chloroplasts. The process involves two stages namely Light dependent and light independent stage. From the light independent stage Hydrogen ions formed from photolysis joins the light independent stage where carbon iv oxide is fixed and simple sugars are generated. During carbon fixation CO2 combines with five-carbon compounds to form 3-phosphoglycerate (PGA), a three carbon molecule that is a metabolic intermediate of light-independent reactions.