This task is about writing a correct answer for the reading comprehension task. Based on the information provided in a given passage, you should identify the shortest continuous text span from the passage that serves as an answer to the given question. Avoid answers that are incorrect or provides incomplete justification for the question.

Q: Passage: Because of the acceptance of miscegenation, Brazil has avoided the binary polarization of society into black and white. In addition, it abolished slavery without a civil war. The bitter and sometimes violent racial tensions that have divided the US are notably absent in Brazil. According to the 2010 census, 6.7% of Brazilians said they were black, compared with 6.2% in 2000, and 43.1% said they were racially mixed, up from 38.5%. In 2010, Elio Ferreira de Araujo, Brazil's minister for racial equality, attributed the increases to growing pride among his country's black and indigenous communities. Question: How do the US and Brazil vary after slavery has ended?

A: violent racial tensions that have divided the US are notably absent in Brazil.
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Q: Passage: Indian astronomer and mathematician Aryabhata (476-550), in his Aryabhatiya (499) introduced a number of trigonometric functions (including sine, versine, cosine and inverse sine), trigonometric tables, and techniques and algorithms of algebra. In 628 AD, Brahmagupta suggested that gravity was a force of attraction. He also lucidly explained the use of zero as both a placeholder and a decimal digit, along with the Hindu-Arabic numeral system now used universally throughout the world. Arabic translations of the two astronomers' texts were soon available in the Islamic world, introducing what would become Arabic numerals to the Islamic World by the 9th century. During the 14th16th centuries, the Kerala school of astronomy and mathematics made significant advances in astronomy and especially mathematics, including fields such as trigonometry and analysis. In particular, Madhava of Sangamagrama is considered the "founder of mathematical analysis". Question: What did Brahmagupta use the number zero for?

A: a placeholder and a decimal digit
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Q: Passage: In 1358, the Sakya viceregal regime installed by the Mongols in Tibet was overthrown in a rebellion by the Phagmodru myriarch Tai Situ Changchub Gyaltsen (13021364). The Mongol Yuan court was forced to accept him as the new viceroy, and Changchub Gyaltsen and his successors, the Phagmodrupa Dynasty, gained de facto rule over Tibet. Question: Which dynasty became ruler of Tibet?

A:
the Phagmodrupa Dynasty
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