What is the isthmus between China and America? What is the explanation of the geographical term isthmus?

The Central American Isthmus is located in the narrow strip of Central America south of Mexico and north of Colombia, bordering the Caribbean Sea in the Atlantic Ocean in the east and the Pacific Ocean in the west. Including seven countries: Guatemala, El Salvador, Honduras, Nicaragua, Costa Rica, Panama and Belize. It covers an area of 523,000 square kilometers and has a population of more than 28.79 million. Most of them are Indo-European mixed-race, followed by Indians, blacks and whites. Most residents believe in Catholicism. The official language of Belize is English, and the other six countries are all Spanish. The terrain is mainly plateau and mountain, which is an extension of the central Cordillera mountain system along the Pacific coast, with many volcanoes and earthquakes; The plain is narrow and distributed in the northeast and coastal areas. Except in mountainous areas, the climate is hot, with an average annual temperature of 23-28℃. The regional distribution of precipitation is obviously different. The annual precipitation in the foothills of the Caribbean Sea is 2000-3000mm, and that in the coastal and inland basins of the Pacific Ocean is 500-1000mm. Rivers are many and short. It is a land bridge connecting the North American continent and the South American continent, and the Panama Canal connecting the Atlantic Ocean and the Pacific Ocean is a shortcut to connect the two oceans with coastal countries, and its geographical position is important. Planting tropical cash crops is the main economic sector, which is rich in bananas, coffee, sugar cane, cotton, sisal, cocoa, tobacco and grain. Forests are widely distributed and animal husbandry is also very important. The industries are mainly light industry and food industry, and there are many small enterprises. As the birthplace of Mayan culture, it was colonized by Spain.

Isthmus is a narrow zone connecting two continents or between continents and peninsula. The former, such as the Suez Isthmus connecting Asia and Africa and the Panama Isthmus connecting North and South America; The latter, such as the Crater isthmus connecting Indo-China Peninsula and Malay Peninsula, and Pelekopsky Gester Moose connecting the Ukrainian mainland of the Soviet Union and Crimea Peninsula. The isthmus is convenient for digging canals to communicate with the waters on both sides of the strait, such as the completed Suez Canal and Panama Canal.