Please answer this: Extract the answer to the question from the following context. Question: How did the railroad center of Texas get its start? Context: By 1860, Houston had emerged as a commercial and railroad hub for the export of cotton. Railroad spurs from the Texas inland converged in Houston, where they met rail lines to the ports of Galveston and Beaumont. During the American Civil War, Houston served as a headquarters for General John Bankhead Magruder, who used the city as an organization point for the Battle of Galveston. After the Civil War, Houston businessmen initiated efforts to widen the city's extensive system of bayous so the city could accept more commerce between downtown and the nearby port of Galveston. By 1890, Houston was the railroad center of Texas.
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Answer: export of cotton

Please answer this: Extract the answer to the question from the following context. Question: __ is usually accomplished by exchanging the requisite instruments in bilateral treaties Context: After their adoption, treaties as well as their amendments have to follow the official legal procedures of the United Nations, as applied by the Office of Legal Affairs, including signature, ratification and entry into force.
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Answer: ratification

Please answer this: Extract the answer to the question from the following context. Question: What do I need to know about idealism to understand it? Context: In philosophy, idealism is the group of philosophies which assert that reality, or reality as we can know it, is fundamentally mental, mentally constructed, or otherwise immaterial. Epistemologically, idealism manifests as a skepticism about the possibility of knowing any mind-independent thing. In a sociological sense, idealism emphasizes how human ideasespecially beliefs and valuesshape society. As an ontological doctrine, idealism goes further, asserting that all entities are composed of mind or spirit. Idealism thus rejects physicalist and dualist theories that fail to ascribe priority to the mind.
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Answer:
manifests as a skepticism about the possibility of knowing any mind-independent thing