Question

The diagram shows how a biofuel called ethanol is produced. Summarise the information by selecting and reporting the main features, and make comparisons where relevant.

Biofuel production: How ethanol is made

Model Answer

The diagram illustrates the cyclical nature of the ethanol production process. It shows that the process is divided into two main stages: the production and consumption of the product. In both stages, carbon dioxide plays a key role.

As a biofuel, ethanol is produced from plants and trees. With sufficient energy from sunlight and carbon dioxide, plants and trees grow until they are ready for harvesting. Once harvested, the plant material undergoes pre-processing to create an intermediary material known as cellulose. This cellulose is then further processed into a complex sugar. When this material is combined with certain microbes, ethanol is produced.

Ethanol has various uses, including as fuel for cars, trucks, airplanes, and other vehicles. When ethanol is used as fuel, carbon dioxide is produced as a byproduct and released into the atmosphere. Once in the atmosphere, this carbon dioxide can once again be absorbed by plants and trees.

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