This task is about reading the given passage and construct a question about the information present in the passage. Construct a question in such a way that (i) it is unambiguous, (ii) it is answerable from the passage, (iii) its answer is unique (iv) its answer is a continuous text span from the paragraph. Avoid creating questions that (i) can be answered correctly without actually understanding the paragraph and (ii) uses same words or phrases given in the passage.

Q: From the years 1500 to 1850, an estimated 3.5 million captives were forcibly shipped from West/Central Africa to Brazil; the territory received the highest number of slaves of any country in the Americas. Scholars estimate that more than half of the Brazilian population is at least in part descended from these individuals. Brazil has the largest population of Afro-descendants outside of Africa. In contrast to the US, during the slavery period and after, the Portuguese colonial government and later Brazilian government did not pass formal anti-miscegenation or segregation laws. As in other Latin countries, intermarriage was prevalent during the colonial period and continued afterward. In addition, people of mixed race (pardo) often tended to marry white, and their descendants became accepted as white. As a result, some of the European descended population also has West African or Amerindian blood. According to the last census of the 20th century, in which Brazilians could choose from five color/ethnic categories with which they identified, 54% of individuals identified as white, 6.2% identified as black, and 39.5% identified as pardo (brown) a broad multi-racial category, including tri-racial persons.

A: How many slaves were shipped from Africa to Brazil between 1500 and 1850?
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Q: Although there were a number of department stores in Australia for much of the 20th Century, including chains such as Grace Bros. and Waltons, many disappeared during the 1980s and 1990s. Today Myer and David Jones, located nationally, are practically the national department stores duopoly in Australia. When Russian-born migrant, Sidney Myer, came to Australia in 1899 he formed the Myer retail group with his brother, Elcon Myer. In 1900, they opened the first Myer department store, in Bendigo, Victoria. Since then, the Myer retail group has grown to be Australia's largest retailer. Both, Myer and David Jones, are up-market chains, offering a wide variety of products from mid-range names to luxury brands. Other retail chain stores such as Target (unrelated to the American chain of the same name), Venture (now defunct), Kmart and Big W, also located nationally, are considered to be Australia's discount department stores. Harris Scarfe, though only operating in four states and one territory, is a department store using both the large full-line and small discount department store formats. Most department stores in Australia have their own credit card companies, each having their own benefits while the discount department stores do not have their own credit card rights.

A: What were some of the original Australian department stores?
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Q: Tonearm skating forces and other perturbations are also picked up by the stylus. This is a form of frequency multiplexing as the control signal (restoring force) used to keep the stylus in the groove is carried by the same mechanism as the sound itself. Subsonic frequencies below about 20 Hz in the audio signal are dominated by tracking effects, which is one form of unwanted rumble ("tracking noise") and merges with audible frequencies in the deep bass range up to about 100 Hz. High fidelity sound equipment can reproduce tracking noise and rumble. During a quiet passage, woofer speaker cones can sometimes be seen to vibrate with the subsonic tracking of the stylus, at frequencies as low as just above 0.5 Hz (the frequency at which a 33 13 rpm record turns on the turntable; 59 Hz exactly on an ideal turntable). Another reason for very low frequency material can be a warped disk: its undulations produce frequencies of only a few hertz and present day amplifiers have large power bandwidths. For this reason, many stereo receivers contained a switchable subsonic filter. Some subsonic content is directly out of phase in each channel. If played back on a mono subwoofer system, the noise will cancel, significantly reducing the amount of rumble that is reproduced.

A:
What would be a cause of low frequency sounds when listening?
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