Human activities like farming, grazing, deforestation, and landfills impact the environment. Farming uses land and chemicals to grow food for humans and raise animals. Deforestation cuts down trees for materials and fuel, reducing forests. Landfills store human waste but must be lined to prevent pollution. The population is decreasing natural land preserves. The 3Rs of reduce, reuse, and recycle can decrease human impacts by applying them to these activities.