Question: "What is different from the norm?" Context: "The second approach to the problem took as its base the notion of class, and defines a set as a class which belongs to other classes, while a proper class is defined as a class which does not belong to other classes. Under the ZermeloFraenkel approach, the axioms impede the construction of a set of all sets which do not belong to themselves. In contrast, under the von Neumann approach, the class of all sets which do not belong to themselves can be constructed, but it is a proper class and not a set." Answer:
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Answer: the von Neumann approach

Question: "Industrial agriculture contrasts with?" Context: "About 75% of the population is employed in subsistence agriculture upon Swazi Nation Land (SNL). In contrast with the commercial farms, Swazi Nation Land suffers from low productivity and investment. This dual nature of the Swazi economy, with high productivity in textile manufacturing and in the industrialised agricultural TDLs on the one hand, and declining productivity subsistence agriculture (on SNL) on the other, may well explain the country's overall low growth, high inequality and unemployment." Answer:
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Answer: subsistence agriculture

Question: "During what length of time were the most upgrades done on the port?" Context: "The port on Montevideo Bay is one of the reasons the city was founded. It gives natural protection to ships, although two jetties now further protect the harbour entrance from waves. This natural port is competitive with the other great port of Rio de la Plata, Buenos Aires. The main engineering work on the port occurred between the years 1870 and 1930. These six decades saw the construction of the port's first wooden pier, several warehouses in La Aguada, the north and south Rambla, a river port, a new pier, the dredged river basin and the La Teja refinery. A major storm in 1923 necessitated repairs to many of the city's engineering works. Since the second half of the 20th century, physical changes have ceased, and since that time the area has degraded due to national economic stagnation." Answer:
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Answer:
six decades