In a process called photosynthesis, plants use carbon dioxide and water, along with energy from sunlight, to produce sugar and oxygen. photosynthesis is represented by the equation 6co2+> c6h12o6+6o2. what must a plant need to produce 4 molecules of sugar? 6 molecules of co2 6 molecules of h2o 18 molecules of co2 24 molecules of h2o