What is the shape of the terrain on the earth?

Topographic distribution characteristics of the United States: The topographical characteristics of the United States are that the east and west sides are high, the middle is low, and there are no east-west mountains. The United States can be roughly divided into three terrain areas. 1. The Appalachian Mountains in the east and the Appalachian Mountains in the lowlands along the Atlantic coast are about 3,000 kilometers long, and the highest peak is Mount Mitchell, with an altitude of 2,037 meters. There are narrow hills and low coastal plains between it and the Atlantic coast. Known as the Atlantic lowlands, it is generally tens of kilometers to 350 kilometers wide and below 200 meters above sea level. The terrain at the junction of the lowlands and the Appalachian Mountains is very different. Rivers pour into the plain from the mountains, forming many waterfalls and rapids, which is called waterfall route. There are many sand mouths, lagoons and swamps along the Atlantic lowlands, and the Florida Peninsula, the largest peninsula in the United States, is located here. It is more than 600 kilometers long from north to south and 200 kilometers wide from east to west. Generally, the altitude is 30-90 meters. The Atlantic coast is the most developed area in the United States. 2. The western part belongs to the Cordillera Mountains, which runs through the western part of North America and is 65,438+0,700 kilometers wide in the United States. This mountain system consists of the Rocky Mountains in the east, the Cascade Mountains in the west, the Sierra Nevada Mountains and the coastal mountains along the Pacific Ocean. The Rocky Mountains extend from Canada's Yukon Plateau in the north to Mexico in the south. This is North America. Rivers in the east of the mountains flow into the Atlantic Ocean, and rivers in the west flow into the Pacific Ocean. All the great rivers in America originate here. There are many mountains, lakes and small waterfalls in the Cascade Mountains, which are called Cascade (meaning small waterfalls). The highest peak of the Sierra Nevada is Mount Whitney, which is 4,465,438 meters above sea level, the highest point in the United States. The "dead valley" on the east side of the Sierra Nevada is 65438 below sea level. Its lowest point is 85 meters below sea level, which is the lowest point in the continental United States. Between the Rocky Mountains and the Cascade and Nevada Mountains, there are the Columbia Plateau, the Colorado Plateau and the inland basin. Among them, the Columbia Plateau is located in the north and the Colorado Plateau is located in the southeast. These two plateaus are flat, but there are also many canyons deeply penetrated by rivers, such as the Grand Canyon where the Colorado River flows, which is 440 kilometers long. Shenda1830m. From Cascade and Sierra Nevada to the west, it is a coastal mountain range that stands steeply on the Pacific coast, with a height of more than 2000 meters. There are two long and narrow valleys between the two mountains: the Witmet Valley in the north; In the south, it is the most important agricultural area in the western United States-the fertile California Valley. 3. The central plain is located between the Appalachian Mountains in the east and the Rocky Mountains in the west, starting from the Great Lakes coast in the north and the bottomless plain in the Gulf of Mexico in the south, running through the whole central United States from north to south, accounting for about 1/2 of the total soil area in the United States. It can be roughly divided into two parts: the eastern plain, generally below 500 meters above sea level, only in the southwest. This is a low platform. Glaciation is obvious in the north of Missouri River and Ohio River, and there are many lake basins. The western great plain, located in the east of the Rocky Mountains and west of the eastern plain, reaches the boundary line from north to south, with an altitude of 500 to 1800 meters, and gradually rises from east to west, which is deeply influenced by the east-west river valley. The plain is flat, fertile and rich in pasture, also known as the prairie, which is the largest in the United States. It borders the Atlantic Ocean in the east, the Pacific Ocean in the west, Canada in the north and Mexico and the Gulf of Mexico in the south. The whole territory can be divided into five geographical regions from east to west: the southeast coastal plain is divided into two parts: the Atlantic coastal plain and the Mexican coastal plain. This area is below 200 meters above sea level, and most of them are alluvial rivers, especially the Mississippi River Delta, which is the largest delta in the world with black soil. The soil is fertile. There are some swamps near the estuary. The Florida Peninsula in this geographical area is the largest peninsula in the United States. Apara Ridge is located on the west side of the Atlantic coastal plain, basically parallel to the coast, with a length of over 2,300 kilometers. Generally, it consists of several parallel mountains with an altitude of 1 0,000 ~10,500 meters. The inland plain is an inverted triangle, and the long border between the United States and Canada is in the north. The Rio Grande on the South Atlantic coastal plain. The western mountain range consists of two mountains in the west, the Rocky Mountains in the east, the Sierra Nevada and the Cascade Mountains in the west, which are the products of old folding movement. Mount Whitney in the Sierra Nevada is 44 18 meters above sea level, which is the highest point in the continental United States. Mount Rainier in the Cascade Mountains is 4392 meters above sea level. The western mountain plateau, second only to Whitney Peak, is composed of Colorado Plateau, Wyoming Plateau, Columbia Plateau and Grand Canyon, which is the most complicated geological structure in the western United States. Located in the northwest of Arizona, the Grand Canyon is composed of a series of winding canyons and deep valleys. It is a rare natural landscape in the world with magnificent momentum and steep rock walls. In the centuries from 2006 to 2008, European powers established colonies in North America. The French established new France (including the lower reaches of the St. Lawrence River and the Mississippi River); The Spanish established the new Spain (including Mexico and a large area in the southwestern United States). /kloc-At the beginning of the 7th century, Britain began to immigrate to North America. The first batch of North American immigrants were mainly farmers who lost their land, workers who had a hard life and Puritans who were persecuted by religion. 1607, a colonial group of about 100 people was forced to return to Britain because of the cold. 1687, 9 1 men, 17 women and 9 children came, and Jamestown was established in Schabik Beach built by Britain in North America. In the next 150 years, many colonists came in and settled in the coastal areas, most of them came from Britain, and some came from France, Germany, the Netherlands, Ireland and other countries. Most of the people who arrived in the colonies were poor working people in western Europe, but there were also nobles, landlords and bourgeoisie, among which the British, Irish, Germans and Dutch were the most. Among the immigrants, there are people who escape from war and religious persecution, voluntary and involuntary "contract slaves", beggars and criminals; And black people trafficked from Africa. 1620, they took the Mayflower to North America and made the Mayflower Convention on board. On June165438+1October 2 1 day, the Puritans landed in Plymouth and signed the Mayflower Convention with 4 1 free adult men. The content is to organize citizen groups; Drafting laws and regulations, etc. Lay the foundation of autonomous government. In the colonial era, with the long-term war with Native American Indians, the serious shortage of labor produced slaves, contract slavery and other non-free labor, and the laissez-faire policy of the British government allowed the unique American spirit and culture to develop its uniqueness. The evil slave trade prevailed in America. From 1607 to 1733, British colonists successively established thirteen colonies on the east coast of North America (Atlantic coast). [15]1In the mid-8th century, the economies, cultures and politics of the colonies were relatively mature. The colonial parliament still believed in King George III of England, but pursued the same status as the British parliament and was unwilling to become a second-class citizen of Britain. But at this time, after the seven-year war between Britain and France, they were so eager to consolidate their territory that they imposed heavy taxes on the colonial people in North America. King George III changed his laissez-faire policy and advocated high-handed means. This led to the resistance of the colonial people, such as "no taxation without representation", "Boston Massacre" and "Intolerance Act". 1775 In April, the "Fires of Lexington" started in Lexington and Concord, which started the American War of Independence. Later, these colonies became the original thirteen independent states in North America.