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Two recent discoveries indicate probable very early settlements near the Thames in the London area. In 1999, the remains of a Bronze Age bridge were found on the foreshore north of Vauxhall Bridge. This bridge either crossed the Thames, or went to a now lost island in the river. Dendrology dated the timbers to 1500 BC. In 2010 the foundations of a large timber structure, dated to 4500 BC, were found on the Thames foreshore, south of Vauxhall Bridge. The function of the mesolithic structure is not known. Both structures are on South Bank, at a natural crossing point where the River Effra flows into the River Thames.
The remains of what type of structure from the mesolithic period was found on the River Thames's foreshore?
A: not known

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To protect crops from wind and drought, the Grain Intendant Zhao Guo () created the alternating fields system (daitianfa ) during Emperor Wu's reign. This system switched the positions of furrows and ridges between growing seasons. Once experiments with this system yielded successful results, the government officially sponsored it and encouraged peasants to use it. Han farmers also used the pit field system (aotian ) for growing crops, which involved heavily fertilized pits that did not require plows or oxen and could be placed on sloping terrain. In southern and small parts of central Han-era China, paddy fields were chiefly used to grow rice, while farmers along the Huai River used transplantation methods of rice production.
What helped insure the safety of crops from wind?
A: the alternating fields system

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Domestic dogs have been selectively bred for millennia for various behaviors, sensory capabilities, and physical attributes. Modern dog breeds show more variation in size, appearance, and behavior than any other domestic animal. Dogs are predators and scavengers, and like many other predatory mammals, the dog has powerful muscles, fused wrist bones, a cardiovascular system that supports both sprinting and endurance, and teeth for catching and tearing.
Dogs are considered to be predators and what else?
A: scavengers

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The Delhi Flying Club, established in 1928 with two de Havilland Moth aircraft named Delhi and Roshanara, was based at Safdarjung Airport which started operations in 1929, when it was the Delhi's only airport and the second in India. The airport functioned until 2001, however in January 2002 the government closed the airport for flying activities because of security concerns following the New York attacks in September 2001. Since then, the club only carries out aircraft maintenance courses, and is used for helicopter rides to Indira Gandhi International Airport for VIP including the president and the prime minister.
In what year did the government close Safdarjung Airport due to security concerns?
A:
2002