The diagram illustrates the production of a type of biofuel known as ethanol. Overall, it can be inferred from the diagram that the process showcases three primary stages: preparation, production and usage. Although human labour might be required during harvesting, the most steps of the work are done by special machinery.
The initial step in the process is carbon dioxide in the atmosphere mixes with sunlight forming energy, allowing vegetation to flourish. Once they are grown, they are harvested with mechanical assistance. After they are taken to the factory, a special machine grinds them into small chunks, a step called pre-processing, creating cellulose.
Moving on to the production phase, work commences by further processing earlier cellulose generating sugar molecules. Microbes are then fermented with sugars ultimately forming ethanol. The process is cyclical, once transportation emits carbon dioxide back to the atmosphere, using produced ethanol, the cycle repeats itself starting from creating energy for plants again.