Please answer this: Extract the answer to the question from the following context. Question: Australian Air Express planes can't land without an? Context: Melbourne has four airports. Melbourne Airport, at Tullamarine, is the city's main international and domestic gateway and second busiest in Australia. The airport is home base for passenger airlines Jetstar Airways and Tiger Airways Australia and cargo airlines Australian air Express and Toll Priority; and is a major hub for Qantas and Virgin Australia. Avalon Airport, located between Melbourne and Geelong, is a secondary hub of Jetstar. It is also used as a freight and maintenance facility. Buses and taxis are the only forms of public transport to and from the city's main airports. Air Ambulance facilities are available for domestic and international transportation of patients. Melbourne also has a significant general aviation airport, Moorabbin Airport in the city's south east that also handles a small number of passenger flights. Essendon Airport, which was once the city's main airport also handles passenger flights, general aviation and some cargo flights.
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Answer: airport


Please answer this: Extract the answer to the question from the following context. Question: How did the campaign gain momentum? Context: In September 2003, retired four-star general Wesley Clark announced his intention to run in the presidential primary election for the Democratic Party nomination. His campaign focused on themes of leadership and patriotism; early campaign ads relied heavily on biography. His late start left him with relatively few detailed policy proposals. This weakness was apparent in his first few debates, although he soon presented a range of position papers, including a major tax-relief plan. Nevertheless, the Democrats did not flock to support his campaign.
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Answer: presented a range of position papers, including a major tax-relief plan


Please answer this: Extract the answer to the question from the following context. Question: What does the process cause to happen to the container? Context: Standing out in Clarke's (and Newton's) response to Leibniz's arguments is the bucket argument: Water in a bucket, hung from a rope and set to spin, will start with a flat surface. As the water begins to spin in the bucket, the surface of the water will become concave. If the bucket is stopped, the water will continue to spin, and while the spin continues, the surface will remain concave. The concave surface is apparently not the result of the interaction of the bucket and the water, since the surface is flat when the bucket first starts to spin, it becomes concave as the water starts to spin, and it remains concave as the bucket stops.
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Answer:
it becomes concave