The given diagram illustrates the progress of produce a biofuel called ethanol.
Overall, the process has three main steps, including the absorption of energy by plants and trees, production and consumpiton of ethanol, and re-absorption of carbon dioxide emission.
At the beginning of the process, energy in form of sunlight and carbon dioxide is absorbed by plants and trees to grow. Once mature, these plants are havested by machines and then enter the phase of pre-processing, before becoming cellulose, which is a chemical component that present in these species.
In the subsequent step, cellulose is processed chemically to become sugars. Microbes are added to sugars in order to turn them into ethanol. The process continues with the utilize of ethanol in various kinds of vehicles such as cars, trucks and planes. Carbon dioxide emission released from these vehicles to the atmosphere, then it is absorbed again by trees and plants, repeating the cycle of making this kind of biofuel.