About twenty-nine percent or 133 million km2 of the earth's surface is made up of land. Contributing to about 2/3 of this area are forests, grasslands, and agriculture. Other categories of land include tundra's, marshes, deserts; scrub forests, urban areas, bare rock, and ice or snow. Deserts and other unproductive lands are important factors in biogeochemical cycles and biological diversity. Because of parks, wildlife refuges, and nature preserves nearly ten percent of the world's land surface is …showed first 75 words of 1412 total…

…showed last 75 words of 1412 total…encourage the growth of more attractive forage species. Forests and grasslands are both extremely important land uses. Forests are important in providing food and shelter for animals as well as regulating the climate and purifying the air. Grasslands support grazing animals who convert dirt into enriched soil for farming and who turn plants into protein for human nutrition. If they keep declining at this pace the world will run out of resources for everyday use.