Please answer the following question: Information: - The United States Antarctic Program (or USAP; formerly known as the United States Antarctic Research Program or USARP and the United States Antarctic Service or USAS) is an organization of the United States government which has presence in the continent of Antarctica. Founded in 1959, the USAP manages all U.S. scientific research and related logistics in Antarctica as well as aboard ships in the Southern Ocean. - Antarctica (US English , UK English or ) is Earth's southernmost continent. It contains the geographic South Pole and is situated in the Antarctic region of the Southern Hemisphere, almost entirely south of the Antarctic Circle, and is surrounded by the Southern Ocean. At , it is the fifth-largest continent. For comparison, Antarctica is nearly twice the size of Australia. About 98% of Antarctica is covered by ice that averages in thickness, which extends to all but the northernmost reaches of the Antarctic Peninsula. - The National Science Foundation (NSF) is a United States government agency that supports fundamental research and education in all the non-medical fields of science and engineering. Its medical counterpart is the National Institutes of Health. With an annual budget of about US$7.0 billion (fiscal year 2012), the NSF funds approximately 24% of all federally supported basic research conducted by the United States' colleges and universities. In some fields, such as mathematics, computer science, economics, and the social sciences, the NSF is the major source of federal backing. - The McMurdo Station is a United States Antarctic research center on the south tip of Ross Island, which is in the New Zealand-claimed Ross Dependency on the shore of McMurdo Sound in Antarctica. It is operated by the United States through the United States Antarctic Program, a branch of the National Science Foundation. The station is the largest community in Antarctica, capable of supporting up to 1,258 residents, and serves as one of three United States Antarctic science facilities. All personnel and cargo going to or coming from AmundsenScott South Pole Station first pass through McMurdo. - McMurdo Sound and its ice-clogged waters extends about long and wide. The sound connects the Ross Sea to the north with the Ross Ice Shelf cavity to the south via Haskell Strait. The strait is largely covered by the McMurdo Ice Shelf. The Royal Society Range rises from sea level to on the western shoreline. Ross Island, an historic jumping-off point for polar explorers, designates the eastern boundary. The active volcano Mt Erebus at dominates Ross Island. Antarctica's largest scientific base, the United States' McMurdo Station, as well as the New Zealand Scott Base are on the southern shore of the island. Less than 10 percent of McMurdo Sound's shoreline is free of ice. It is the southernmost navigable body of water in the world. - New Zealand is an island nation in the southwestern Pacific Ocean. The country geographically comprises two main landmassesthat of the North Island, or Te Ika-a-Mui, and the South Island, or Te Waipounamuand numerous smaller islands. New Zealand is situated some east of Australia across the Tasman Sea and roughly south of the Pacific island areas of New Caledonia, Fiji, and Tonga. Because of its remoteness, it was one of the last lands to be settled by humans. During its long period of isolation, New Zealand developed a distinct biodiversity of animal, fungal and plant life. The country's varied topography and its sharp mountain peaks, such as the Southern Alps, owe much to the tectonic uplift of land and volcanic eruptions. New Zealand's capital city is Wellington, while its most populous city is Auckland. - The Scott Base is a New Zealand Antarctic research facility located at Pram Point on Ross Island near Mount Erebus in New Zealand's Ross Dependency territorial claim. The research facility was named in honour of Captain Robert Falcon Scott, RN, leader of two British expeditions to the Ross Sea area of Antarctica. The base was set up as support to field research and the centre for research into earth sciences, and now conducts research in many fields, operated by Antarctica New Zealand. - Williams Field or Willy Field is a United States Antarctic Program airfield in Antarctica. Williams Field consists of two snow runways located on approximately 8 meters (25ft) of compacted snow, lying on top of 810ft of ice, floating over 550 meters (1,800ft) of water. The airport, which is approximately seven miles from Ross Island, serves McMurdo Station and New Zealands Scott Base. Until the 2009-10 summer season, Williams was the major airfield for on-continent aircraft operations in Antarctica. - The AmundsenScott South Pole Station is a United States scientific research station at the South Pole, the southernmost place on the Earth. The station is located on the high plateau of Antarctica at an elevation of above sea level and is administered by the Division of Polar Programs within the National Science Foundation under the United States Antarctic Program. - A research center is a facility or building dedicated to research, commonly with the focus on a specific area. There are over 14,000 research centers in the United States. Centers apply varied disciplines including basic research and applied research in addition to non traditional techniques. However, a research center should not be confused with a research institute. Additionally, today many universities are establishing research centers to conduct a specific research or education activity. Over a hundred of research centers can be established in one university. This number certainly differs from a university to a university, but most of the research centers there do bring something to the scientific table. - The Ice Runway ( ICAO : NZIR ) is the principal runway for the US Antarctic Program during the summer Antarctic field season due to its proximity to McMurdo Station . The other two runways in the area are the snow runway at Williams Field ( ICAO : NZWD ) and the white ice runway at Pegasus Field ( ICAO : NZPG ) . This runway is capable of handling wheeled aircraft , that have included to date : Lockheed C - 5 Galaxy , Lockheed C - 141 Starlifter , Boeing C - 17 Globemaster III , Lockheed C - 130 Hercules and Lockheed P - 3 Orion . In the summer season of 2009/2010 the RNZAF trialled a modified Boeing 757 operationally . The intention is to use the Boeing 757 for passenger transport thereby freeing up capacity for C17 cargo space . The annual sea - ice runway for wheeled aircraft is constructed at the start of each season and is used until early December when the sea ice begins to break up . Subsequently flight operations are moved back to Williams Field . Pilots landing C - 17 Globemaster III cargo aircraft on the sea ice runway report that the surface is stable , not unlike landing on concrete . However , the similarity with land bases ends when the jet aircraft rolls to a stop . The nearly 450,000 pound ( = 201 tons ) weight of the plane , including cargo and passengers , causes it to sink into the ice , albeit only a matter of inches . A laser light is trained on the aircraft to measure the settlement rate . The $ 200 million aircraft is moved to a new location on the six - foot - thick ice as a safety measure if the 10 - inch red line is reached , according to the News Tribune in Tacoma , Washington . - Ross Island is an island formed by four volcanoes in the Ross Sea near the continent of Antarctica, off the coast of Victoria Land in McMurdo Sound. - Science is a systematic enterprise that builds and organizes knowledge in the form of testable explanations and predictions about the universe. - Pegasus Field was an airstrip in Antarctica, the southernmost of three airfields serving McMurdo Station. It closed due to excessive melting in the summer season caused by warmer temperatures combined with dust and dirt blown in from nearby Black Island. The last flight was on December 8, 2016 and it was replaced by Phoenix Airfield with flights expected to start in February 2017. - The Ross Dependency is a region of Antarctica defined by a sector originating at the South Pole, passing along longitudes 160 east to 150 west, and terminating at latitude 60 south. It is claimed by New Zealand. Since the Antarctic Treaty came into force in 1961, Article IV of which states: "No acts or activities taking place while the present Treaty is in force shall constitute a basis for asserting, supporting or denying a claim to territorial sovereignty in Antarctica or create any rights of sovereignty in Antarctica," most countries do not recognise territorial claims in Antarctica. After reading the paragraphs above, we are interested in knowing the entity with which 'ice runway' exhibits the relationship of 'instance of'. Find the answer from the choices below. Choices: - 1 - 25 - activity - addition - aircraft - airport - airstrip - article - base - branch - building - capital - circle - city - continent - country - december - division - economics - education - elevation - enterprise - facility - field - force - foundation - government - government agency - health - hundred - island - jumping - nation - ocean - phoenix - point - pole - range - region - research - research center - research institute - research program - research station - rights - science - sea - season - sector - service - size - snow - society - sound - station - tectonic uplift - three - treaty - two - university
A:
airport