[Q]: Extract the answer to the question from the following context. Question: What alternative to artificial heat provides buoyancy? Context: A solar balloon is a black balloon that is filled with ordinary air. As sunlight shines on the balloon, the air inside is heated and expands causing an upward buoyancy force, much like an artificially heated hot air balloon. Some solar balloons are large enough for human flight, but usage is generally limited to the toy market as the surface-area to payload-weight ratio is relatively high.
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[A]: sunlight

[Q]: Extract the answer to the question from the following context. Question: How does the constitution function? Context: Similarly, the federal constitutional initiative allows citizens to put a constitutional amendment to a national vote, if 100,000 voters sign the proposed amendment within 18 months.[note 8] Parliament can supplement the proposed amendment with a counter-proposal, and then voters must indicate a preference on the ballot in case both proposals are accepted. Constitutional amendments, whether introduced by initiative or in Parliament, must be accepted by a double majority of the national popular vote and the cantonal popular votes.[note 9]
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[A]: Constitutional amendments, whether introduced by initiative or in Parliament, must be accepted by a double majority of the national popular vote and the cantonal popular votes

[Q]: Extract the answer to the question from the following context. Question: Where will you see the main idea of this ideal beginning to be applied? Context: The Rule of Law is especially important as an influence on the economic development in developing and transitional countries. To date, the term "rule of law" has been used primarily in the English-speaking countries, and it is not yet fully clarified even with regard to such well-established democracies as, for instance, Sweden, Denmark, France, Germany, or Japan. A common language between lawyers of common law and civil law countries as well as between legal communities of developed and developing countries is critically important for research of links between the rule of law and real economy.
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[A]: developing and transitional countries

[Q]: Extract the answer to the question from the following context. Question: Valencia being an episcopal See was under the control of Context: A few centuries later, coinciding with the first waves of the invading Germanic peoples (Suevi, Vandals and Alans, and later the Visigoths) and the power vacuum left by the demise of the Roman imperial administration, the church assumed the reins of power in the city and replaced the old Roman temples with religious buildings. With the Byzantine invasion of the southwestern Iberian peninsula in 554 the city acquired strategic importance. After the expulsion of the Byzantines in 625, Visigothic military contingents were posted there and the ancient Roman amphitheatre was fortified. Little is known of its history for nearly a hundred years; although this period is only scarcely documented by archeology, excavations suggest that there was little development of the city. During Visigothic times Valencia was an episcopal See of the Catholic Church, albeit a suffragan diocese subordinate to the archdiocese of Toledo, comprising the ancient Roman province of Carthaginensis in Hispania.
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[A]:
archdiocese of Toledo