The diagram illustrates the cycle of producing a biofuel that is called Ethanol.
Overall, the process of producing the ethanol consists of ten stages, beginning with the solar energy and ending with the carbon dioxide.
In the first stage, Trees and plants for growing needed solar energy and they are gotten sunlight and carbon dioxide then they are harvested by agriculture equipment and transported to pre-processing where they are crushed. In the next stage they are transformed into cellulose and starting the chemical process.
Then, sugar is produced by chemical reactions then added to microbial cells for fermentation process after that process Ethanol is produced by fermentation and converted to gas fuel for using vehicles such as cars, trucks or airplanes. In the end vehicles are consumed ethanol and produce carbon dioxide.