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Copper is synthesized in massive stars and is present in the Earth's crust at a concentration of about 50 parts per million (ppm), where it occurs as native copper or in minerals such as the copper sulfides chalcopyrite and chalcocite, the copper carbonates azurite and malachite, and the copper(I) oxide mineral cuprite. The largest mass of elemental copper discovered weighed 420 tonnes and was found in 1857 on the Keweenaw Peninsula in Michigan, US. Native copper is a polycrystal, with the largest described single crystal measuring 4.43.23.2 cm.
What year was the smallest find of copper discovered?
A: unanswerable

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Houston's economy has a broad industrial base in energy, manufacturing, aeronautics, and transportation. It is also leading in health care sectors and building oilfield equipment; only New York City is home to more Fortune 500 headquarters within its city limits. The Port of Houston ranks first in the United States in international waterborne tonnage handled and second in total cargo tonnage handled. Nicknamed the Space City, Houston is a global city, with strengths in business, international trade, entertainment, culture, media, fashion, science, sports, technology, education, medicine and research. The city has a population from various ethnic and religious backgrounds and a large and growing international community. Houston is the most diverse city in Texas and has been described as the most diverse in the United States. It is home to many cultural institutions and exhibits, which attract more than 7 million visitors a year to the Museum District. Houston has an active visual and performing arts scene in the Theater District and offers year-round resident companies in all major performing arts.
What is varied about Houston's population?
A: ethnic and religious backgrounds

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Portuguese universities have existed since 1290. The oldest Portuguese university was first established in Lisbon before moving to Coimbra. Historically, within the scope of the Portuguese Empire, the Portuguese founded the oldest engineering school of the Americas (the Real Academia de Artilharia, Fortificacao e Desenho of Rio de Janeiro) in 1792, as well as the oldest medical college in Asia (the Escola Medico-Cirurgica of Goa) in 1842. The largest university in Portugal is the University of Lisbon.
What is the oldest medical college in Asia?
A: the Escola Medico-Cirurgica of Goa

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Though pesticide regulations differ from country to country, pesticides, and products on which they were used are traded across international borders. To deal with inconsistencies in regulations among countries, delegates to a conference of the United Nations Food and Agriculture Organization adopted an International Code of Conduct on the Distribution and Use of Pesticides in 1985 to create voluntary standards of pesticide regulation for different countries. The Code was updated in 1998 and 2002. The FAO claims that the code has raised awareness about pesticide hazards and decreased the number of countries without restrictions on pesticide use.
In what areas do agriculture methods differ?
A:
unanswerable