More than 450 landfills in the united states now use biogas to

More than 450 landfills in the United States now use biogas to generate electricity and heat homes.
In United States landfill are already gathering biogas for use in energy projects. The landfill is into a top of the ground in which trash is isolated from the surrounding environment.

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The changes to agriculture in the united states since 1900 is that increased mechanization has increased food production, thereby increasing the need for labor. there has been an increased need for higher speeds of food production due the fact that the population in the united states continues to rise.