Mountains,Valleys,Hills.
Explanation:
Mountains: r lands physical features protruding high beyond the hills & very high up the land surface with steep top commonly shaped up to a peak. They r created through the action of incredible forces n the earth such as volcanic eruptions. Often, mountains occur n the ocean compared to land & some are seen as mountain islands as their peaks protrude out of the water. Mountain formation result from the forces of erosion, volcanism, or uplifts n the earth’s crust.The forces of heat & pressure within the earth’s interior r the main influencing factors to these forces as stated by geologists. These forces can be summed up as the plate tectonic movements – theoretically defined as the division of the earth’s outermost layer into several plates which r n constant motion. Hence, the uplifts r caused by collision or pulling apart of the plates that also triggers other various geologic activities such as the ejection of magma onto the surface or volcanic eruptions.The movements also contribute to horizontal compression that is the deformation of crustal strata which gives rise to folds. The Himalayas & the Europe’s Jura & Alps mountains r examples of mountains formed as a result of horizontal compression. Some mountain ranges r also formed as a result of wind, water, & ice erosion. Other mountains r created from volcanoes.Examples of volcanic mountains include Mount Fuji n Japan, Mount Vesuvius n Italy, Mount Erebus n Antarctica, & Mount Saint Helens n the US. Majority of volcanic mountains have summit craters that still expel debris & steam.
Valley: is a lowland area or surface depression of the earth between higher lands such as mountains or hills. In simple terms, it can be defined as a natural trough bounded by mountains or hills on the surface of the earth sloping down to the lake, ocean or stream, which is created because of water or ice erosion. On this basis, the rivers or streams flowing through the valley empty the land’s precipitation into the oceans.The lowest parts of the valleys r very fertile & make very good farmlands. Majority of the valleys on land r made up of running streams & rivers & nearly all their floors slope downstream. Valleys within the mountains normally have narrow floors. The sides of a valley r termed as valley slopes or valley walls & the section of floor along riverbanks r referred to as flood plains.Valleys physical features include U-shaped & V-shaped caused through the forces of erosion by the flowing masses that persistently widens & deepens the valley. The flowing masses r either water or glacier that carries away huge amounts of debris. Very narrow & deep valleys r known as canyons.
Hills: R raised areas on the surface of the earth with distinctive summits, but r not as high as mountains. Hills r created as a result of accumulation of rock debris or sand deposited by wind & glaciers. They can also be created by faulting when the faults go slightly upwards. Hills r generally present n low mountain valleys & plains.The Black Hills r the most known. Deep erosions of areas previously raised by the earth’s crust disturbances carry most of the soil away leaving behind a hill. Human activities may also create hill when soils r dug & piled giant masses. Volcanic eruptions as well create hills after the eruption when the molten materials or lava cools & hardens n a pile.
