In this task, you are given a question and a context passage. You have to answer the question based on the given passage.

Q: What is a legal doctrine that obligates courts to follow historical cases when making a ruling on a similar case, Context: Federal law originates with the Constitution, which gives Congress the power to enact statutes for certain limited purposes like regulating interstate commerce. The United States Code is the official compilation and codification of the general and permanent federal statutes. Many statutes give executive branch agencies the power to create regulations, which are published in the Federal Register and codified into the Code of Federal Regulations. Regulations generally also carry the force of law under the Chevron doctrine. Many lawsuits turn on the meaning of a federal statute or regulation, and judicial interpretations of such meaning carry legal force under the principle of stare decisis.

A: stare decisis
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Q: Which country has less than 650,000 elevators installed as of January 2008, the United States or China?, Context: As of January 2008, Spain is the nation with the most elevators installed in the world, with 950,000 elevators installed that run more than one hundred million lifts every day, followed by United States with 700,000 elevators installed and China with 610,000 elevators installed since 1949. In Brazil, it is estimated that there are approximately 300,000 elevators currently in operation. The world's largest market for elevators is Italy, with more than 1,629 million euros of sales and 1,224 million euros of internal market.

A: China
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Q: Who provided food for the underground shelters?, Context: Public demand caused the government in October 1940 to build new deep shelters:189–190 within the Underground to hold 80,000 people but were not completed until the period of heaviest bombing had passed. By the end of 1940 significant improvements had been made in the Underground and in many other large shelters. Authorities provided stoves and bathrooms and canteen trains provided food. Tickets were issued for bunks in large shelters to reduce the amount of time spent queuing. Committees quickly formed within shelters as informal governments, and organisations such as the British Red Cross and the Salvation Army worked to improve conditions. Entertainment included concerts, films, plays and books from local libraries.

A:
canteen trains
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