The Amazon Plain, located in the northern part of South America, in the middle and lower reaches of the Amazon River, covers an area of ​​5.6 million square kilometers (of which more than 2.2 million square kilometers are in Brazil, accounting for about 1/3 of the country's territory), and is the largest alluvial plain in the world. The Amazon Plain is densely covered with tropical rainforests, with a wide variety of plant species and rich endemic species; animal species are also very rich, especially arboreal animals. The main mineral deposits are oil. It is sparsely populated, with a total population of about 15 million, including 100,000 Indians living in the dense forest.

The eastern United States is an ancient mountain formed by the Appalachian Mountains and the Atlantic coastal plains; the southeastern part has a subtropical humid climate. The average annual precipitation is more than 1,500 mm. The climate in the northeast is basically continental, with cold winters and hot summers, high temperatures and high humidity. Although the average temperature here is very high, it is often invaded by cold currents from the north.

Northeast China has a temperate monsoon climate with warm and humid summers and cold and dry winters. It is surrounded by mountains on three sides and the Northeast Plain in the middle. Therefore, it is characterized by mountains surrounding water and a plain in the middle. The Northeast region is surrounded by mountains on the west, north and east and faces the sea on the south, which is conducive to the entry of moist air into the inland and the formation of precipitation.

Northwest China, the terrain of the northwest region is mainly plateaus, basins and mountains. The Inner Mongolia Plateau and its Hulunbuir Plateau, Hetao Plain, Ningxia Plain, and Ordos Plateau. Mountains and basins alternate in Xinjiang: Altai Mountains, Junggar Basin, Tianshan Mountains, Tarim Basin, Kunlun Mountains, and Altun Mountains. Turpan Basin. Most of them are temperate continental climates, hot during the day, cold at night, large temperature differences, and little precipitation.

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