Given the question: Information:  - Magma (from Ancient Greek  ("mágma") meaning "thick unguent") is a mixture of molten or semi-molten rock, volatiles and solids that is found beneath the surface of the Earth, and is expected to exist on other terrestrial planets and some natural satellites. Besides molten rock, magma may also contain suspended crystals, dissolved gas and sometimes gas bubbles. Magma often collects in magma chambers that may feed a volcano or solidify underground to form an intrusion. Magma is capable of intruding into adjacent rocks (forming igneous dikes and sills), extrusion onto the surface as lava, and explosive ejection as tephra to form pyroclastic rock.  - A canyon (Spanish: cañón) or gorge is a deep cleft between escarpments or cliffs resulting from the erosive activity of a river over geologic timescales. Rivers have a natural tendency to cut through underlying surfaces so will eventually wear away rock layers to lessen their own pitch slowing their waters; given enough time, their bottoms will gradually reach a baseline elevationwhich is the same elevation as the body of water it will eventually drain into. This action, when the river source and mouth are at much different base elevations will form a canyon, particularly through regions where softer rock layers are intermingled with harder layers more resistant to weathering.  - A landform is a natural feature of the solid surface of the Earth or other planetary body. Landforms together make up a given terrain, and their arrangement in the landscape is known as topography. Typical landforms include hills, mountains, plateaus, canyons, valleys, as well as shoreline features such as bays, peninsulas, and seas, including submerged features such as mid-ocean ridges, volcanoes, and the great ocean basins.  - Earth, otherwise known as the world, is the third planet from the Sun and the only object in the Universe known to harbor life. It is the densest planet in the Solar System and the largest of the four terrestrial planets.  - Volcanic gases include a variety of substances given off by active (or, at times, by dormant) volcanoes. These include gases trapped in cavities (vesicles) in volcanic rocks, dissolved or dissociated gases in magma and lava, or gases emanating directly from lava or indirectly through ground water heated by volcanic action.  - A planetary body or planetary object is any secondary body in the Solar System that is geologically differentiated or in hydrostatic equilibrium and thus has a planet-like geology: a planet, dwarf planet, or the larger moons and asteroids.  - In hillslope geomorphology, a rill is a shallow channel (no more than a few tens of centimetres deep) cut into soil by the erosive action of flowing water. Similar but smaller incised channels are known as microrills; larger incised channels are known as gullies.  - A valley is a low area between hills, often with a river running through it.  - A bay is a body of water connected to an ocean or lake, formed by an indentation of the shoreline. A large bay may be called a "gulf", a "sea", a "sound", or a "bight". A "cove" is a smaller circular or oval coastal inlet with a narrow entrance; some coves may be referred to as bays. A "fjord" is a particularly steep bay shaped by glacial activity.  - A sea is a large body of salt water that is surrounded in whole or in part by land. More broadly, "the sea" is the interconnected system of Earth's salty, oceanic watersconsidered as one global ocean or as several principal oceanic divisions. The sea moderates Earth's climate and has important roles in the water cycle, carbon cycle, and nitrogen cycle. Although the sea has been traveled and explored since prehistory, the modern scientific study of the seaoceanographydates broadly to the British "Challenger" expedition of the 1870s. The sea is conventionally divided into up to five large oceanic sectionsincluding the International Hydrographic Organization's four named oceans (the Atlantic, Pacific, Indian, and Arctic) and the Southern Ocean; smaller, second-order sections, such as the Mediterranean, are known as "seas".  - A LAND (Local Area Network Denial) attack is a DoS (Denial of Service) attack that consists of sending a special poison spoofed packet to a computer, causing it to lock up. The security flaw was first discovered in 1997 by someone using the alias "m3lt", and has resurfaced many years later in operating systems such as Windows Server 2003 and Windows XP SP2.  - A mountain is a large landform that stretches above the surrounding land in a limited area , usually in the form of a peak . A mountain is generally steeper than a hill . Mountains are formed through tectonic forces or volcanism . These forces can locally raise the surface of the earth . Mountains erode slowly through the action of rivers , weather conditions , and glaciers . A few mountains are isolated summits , but most occur in huge mountain ranges . High elevations on mountains produce colder climates than at sea level . These colder climates strongly affect the ecosystems of mountains : different elevations have different plants and animals . Because of the less hospitable terrain and climate , mountains tend to be used less for agriculture and more for resource extraction and recreation , such as mountain climbing . The highest mountain on Earth is Mount Everest in the Himalayas of Asia , whose summit is 8,850 m ( 29,035 ft ) above mean sea level . The highest known mountain on any planet in the Solar System is Olympus Mons on Mars at 21,171 m ( 69,459 ft ) .  - Terrain or relief (also topographical relief) is the vertical and horizontal dimension of the land surface. When relief is described underwater, the term bathymetry is used. The Latin Word "Terra (The root word of terrain)," is "Earth."  - A river is a natural flowing watercourse, usually freshwater, flowing towards an ocean, sea, lake or another river. In some cases a river flows into the ground and becomes dry at the end of its course without reaching another body of water. Small rivers can be referred to using names such as stream, creek, brook, rivulet, and rill. There are no official definitions for the generic term river as applied to geographic features, although in some countries or communities a stream is defined by its size. Many names for small rivers are specific to geographic location; examples are "run" in some parts of the United States, "burn" in Scotland and northeast England, and "beck" in northern England. Sometimes a river is defined as being larger than a creek, but not always: the language is vague.  - Volcanic rock (often shortened to volcanics in scientific contexts) is a rock formed from magma erupted from a volcano. In other words, it differs from other igneous rock by being of volcanic origin. Like all rock types, the concept of volcanic rock is artificial, and in nature volcanic rocks grade into hypabyssal and metamorphic rocks and constitute an important element of some sediments and sedimentary rocks. For these reasons, in geology, volcanics and shallow hypabyssal rocks are not always treated as distinct. In the context of Precambrian shield geology, the term "volcanic" is often applied to what are strictly metavolcanic rocks.  - In geology and earth science, a plateau (or ; plural plateaus or plateaux), also called a high plain or tableland, is an area of highland, usually consisting of relatively flat terrain that is raised significantly above the surrounding area, often with one or more sides with steep slopes.  - A mid-ocean ridge is an underwater mountain system formed by plate tectonics. It consists of various mountains linked in chains, typically having a valley known as a rift running along its spine. This type of oceanic mountain ridge is characteristic of what is known as an oceanic spreading center, which is responsible for seafloor spreading. The production of new seafloor results from mantle upwelling in response to plate spreading; this isentropic upwelling solid mantle material eventually exceeds the solidus and melts. The buoyant melt rises as magma at a linear weakness in the oceanic crust, and emerges as lava, creating new crust upon cooling. A mid-ocean ridge demarcates the boundary between two tectonic plates, and consequently is termed a divergent plate boundary.  - Volcanism is the phenomenon of eruption of molten rock (magma) onto the surface of the Earth or a solid-surface planet or moon, where lava, pyroclastics and volcanic gases erupt through a break in the surface called a vent. It includes all phenomena resulting from and causing magma within the crust or mantle of the body, to rise through the crust and form volcanic rocks on the surface.  - Lava is the molten rock expelled by a volcano during an eruption. The resulting rock after solidification and cooling is also called "lava". The molten rock is formed in the interior of some planets, including Earth, and some of their satellites. The source of the heat that melts the rock within the earth is geothermal energy. When first erupted from a volcanic vent, lava is a liquid usually at temperatures from .   - Topography is the study of the shape and features of the surface of the Earth and other observable astronomical objects including planets, moons, and asteroids. The topography of an area could refer to the surface shapes and features themselves, or a description (especially their depiction in maps).     After reading the paragraphs above, we are interested in knowing the entity with which 'mountain' exhibits the relationship of 'part of'. Find the answer from the choices below.  Choices: - alias  - bay  - body  - center  - computer  - earth  - geology  - geomorphology  - life  - liquid  - local area network  - lock  - may  - mixture  - mouth  - nature  - ocean  - phenomenon  - production  - river  - rock  - sea  - solar system  - solid  - sun  - universe  - variety  - volcano  - weather  - windows xp  - word
The answer is:
geomorphology