Problem: What is the largest castle in Wales
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A: caerphilly

Problem: What is the name for the highly viscous layer of the earth that is about 2,890 km (1,800 miles) thick and makes up about 84 percent of Earth's volume?
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A: mantle

Problem: What colour are the seats in the House of Commons?
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A: green

Problem: The martial art vovinam originated in which country?
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A:
vietnam