They are plants that when fixing CO2 in photosynthesis to create glucose use 4 carbons, reduce leaf photorepiration and water consumption, thus make them more drought resistant and therefore more cost effective. Most of the plants are C3. Many current research is aimed at transforming the C3 pathway of photosynthesis into C4. The process of photosynthesis in plant life uses light, CO2 and water. The thing seems simple but it's not. For me it is one of the mysteries of life.
