Corn, also called maize is a grain plant. It is the kernels of leafy stalk covered with large narrow leaves, usually white or yellow but also have red, purple and blue. Majority of the nutrients are hold in the seeds of kernels. It is one of the most widely cultivated around the world.

Different types of corn will have different usage: sweet corn is usually grown for human consumption; field corn is for livestock feed; some of corns are used in producing ethanol fuel and other biofuel. Ethanol can be mixed with gasoline to decrease the pollutants' amount emitted by fuel motor vehicles; part of the corn plant becomes raw materials in industry.