Our earth is made up 78 percent of water, and rest of it is land. Because of this, there is ample number of living organisms in land as well as water. It has plains, plateaus, mountains, valleys, deserts, forests, grasslands, oceans, seas, rivers, lakes etc. As there are various kinds of regions on earth, every region has its own kind of wild life as well as plant life. Earth has undergone a gradual change in its environment through its years of evolution.
Our earth and its diverse environment: Plateaus, plains and valleys
Plateaus: A plateau is a large highland area of fairly level land separated from surrounding land by steep slopes. Some plateaus, like the plateau of Tibet, lie between mountain ranges. Others are higher than surrounding land. Plateaus are widespread, and together with enclosed basins they cover about 45 percent of the Earth’s land surface.
Plains: plains are broad, nearly level stretches of land that have no great changes in elevation. Plains are generally lower than the land around them; they may be found along a coast or inland. Coastal plains generally rise from sea level until they meet higher landforms such as mountains or plateaus. Inland plains may be found at high altitudes.
Valleys: A valley is a hollow or surface depression of the earth bounded by hills or mountains, a natural trough in the earth’s surface, that slopes down to a stream, lake or the ocean, formed by water and/or ice erosion. Systems of valleys extend through plains, hills, and mountains. Rivers and streams flowing through valleys drain interior land regions to the ocean. At the bottom of many valleys is fertile soil, which makes excellent farmland. Most valleys on dry land are formed by running water of streams and rivers.