Please answer this: Given the following passage "Relations between the Rus' and Byzantines became more complex after Oleg took control over Kiev, reflecting commercial, cultural, and military concerns. The wealth and income of the Rus' depended heavily upon trade with Byzantium. Constantine Porphyrogenitus described the annual course of the princes of Kiev, collecting tribute from client tribes, assembling the product into a flotilla of hundreds of boats, conducting them down the Dnieper to the Black Sea, and sailing to the estuary of the Dniester, the Danube delta, and on to Constantinople. On their return trip they would carry silk fabrics, spices, wine, and fruit. The importance of this trade relationship led to military action when disputes arose. The Primary Chronicle reports that the Rus' attacked Constantinople again in 907, probably to secure trade access. The Chronicle glorifies the military prowess and shrewdness of Oleg, an account imbued with legendary detail. Byzantine sources do not mention the attack, but a pair of treaties in 907 and 911 set forth a trade agreement with the Rus', the terms suggesting pressure on the Byzantines, who granted the Rus' quarters and supplies for their merchants and tax-free trading privileges in Constantinople.", answer the following question. Note that the answer is present within the text. Question: Between Oleg and Kiev, who took control over whom?
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Answer: Oleg took control over Kiev

Please answer this: Given the following passage "Many, if not most, birds migrate in flocks. For larger birds, flying in flocks reduces the energy cost. Geese in a V-formation may conserve 1220% of the energy they would need to fly alone. Red knots Calidris canutus and dunlins Calidris alpina were found in radar studies to fly 5 km/h (3.1 mph) faster in flocks than when they were flying alone.", answer the following question. Note that the answer is present within the text. Question: How many birds migrate in flocks?
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Answer: most

Please answer this: Given the following passage "With the onset of the Crusades in 1095, and the expulsions from England (1290), France (1394), and parts of Germany (15th century), Jewish migration pushed eastward into Poland (10th century), Lithuania (10th century), and Russia (12th century). Over this period of several hundred years, some have suggested, Jewish economic activity was focused on trade, business management, and financial services, due to several presumed factors: Christian European prohibitions restricting certain activities by Jews, preventing certain financial activities (such as "usurious" loans) between Christians, high rates of literacy, near universal male education, and ability of merchants to rely upon and trust family members living in different regions and countries.", answer the following question. Note that the answer is present within the text. Question: How was Poland effected by the Crusades?
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Answer:
Jewish migration