Mexico occupies about 58% of the land of Middle (central) America and contains about 72% of the population of the region. The term 'altiplano' applies to highland cultivation in the South American Andes. Lake Titicaca is the highest fresh water lake on earth and is located in Zambia. In-bond industries are characteristic of US-Mexican border cities. Tropical Rain forest in South America contributes to about 50% of the global oxygen supply. Mexico's major export mineral is copper. Mexico's southern region enjoys desert climate. Yucatan peninsula is the poorest part of Mexico its fragile tropical rain forest climate and less productive limestone soils. Baja California is a major physical region in the United States. Mexico's Gulf Coast region dominated by huge petrochemical and textile industries, rich volcanic soils and large tropical rainforest is by the most prosperous region in Mexico. The Treaty of Tordesillas was signed between Brazil and Mexico. The Amazon River basin is the largest river basin in the world. Llanos is a special type cropland found in the southern coast of Chile. Brazil produces so much of sugarcane that cane juice is converted into alcohol and used as auto fuel. Venezuela's Maracaibo low land is one of the largest petroleum reserve in the world. The Pampas is the leading wheat and cattle producing region in Argentina