In this task, you are given a question and a context passage. You have to answer the question based on the given passage.

Why did the Ottonian dynasty get replaced by the Salian dynasty?, Context: During the early High Middle Ages, Germany was ruled by the Ottonian dynasty, which struggled to control the powerful dukes ruling over territorial duchies tracing back to the Migration period. In 1024, they were replaced by the Salian dynasty, who famously clashed with the papacy under Emperor Henry IV (r. 1084–1105) over church appointments as part of the Investiture Controversy. His successors continued to struggle against the papacy as well as the German nobility. A period of instability followed the death of Emperor Henry V (r. 1111–25), who died without heirs, until Frederick I Barbarossa (r. 1155–90) took the imperial throne. Although he ruled effectively, the basic problems remained, and his successors continued to struggle into the 13th century. Barbarossa's grandson Frederick II (r. 1220–1250), who was also heir to the throne of Sicily through his mother, clashed repeatedly with the papacy. His court was famous for its scholars and he was often accused of heresy. He and his successors faced many difficulties, including the invasion of the Mongols into Europe in the mid-13th century. Mongols first shattered the Kievan Rus' principalities and then invaded Eastern Europe in 1241, 1259, and 1287.
struggled to control the powerful dukes ruling over territorial duchies

Why were 78s more popular than 45s in 1954-55?, Context: Some of Elvis Presley's early singles on Sun Records might have sold more copies on 78 than on 45. This is because the majority of those sales in 1954–55 were to the "hillbilly" market in the South and Southwestern United States, where replacing the family 78 rpm player with a new 45 rpm player was a luxury few could afford at the time. By the end of 1957, RCA Victor announced that 78s accounted for less than 10% of Presley's singles sales, essentially announcing the death throes of the 78 rpm format. The last Presley single released on 78 in the United States was RCA Victor 20-7410, I Got Stung/One Night (1958), while the last 78 in the UK was RCA 1194, A Mess Of Blues/Girl Of My Best Friend (1960).
replacing the family 78 rpm player with a new 45 rpm player was a luxury few could afford

Where did non black residents go to further cause problems for African Americans?, Context: Detroit remains one of the most racially segregated cities in the United States. From the 1940s to the 1970s a second wave of Blacks moved to Detroit to escape Jim Crow laws in the south and find jobs. However, they soon found themselves excluded from white areas of the city—through violence, laws, and economic discrimination (e.g., redlining). White residents attacked black homes: breaking windows, starting fires, and exploding bombs. The pattern of segregation was later magnified by white migration to the suburbs. One of the implications of racial segregation, which correlates with class segregation, may be overall worse health for some populations.

redlining