Here is a question about this article: In nature, the red color of blood comes from hemoglobin, the iron-containing protein found in the red blood cells of all vertebrates. The red color of the Grand Canyon and other geological features is caused by hematite or red ochre, both forms of iron oxide. It also causes the red color of the planet Mars. The red sky at sunset and sunrise is caused by an optical effect known as Rayleigh scattering, which, when the sun is low or below the horizon, increases the red-wavelength light that reaches the eye. The color of autumn leaves is caused by pigments called anthocyanins, which are produced towards the end of summer, when the green chlorophyll is no longer produced. One to two percent of the human population has red hair; the color is produced by high levels of the reddish pigment pheomelanin (which also accounts for the red color of the lips) and relatively low levels of the dark pigment eumelanin.
What is the answer to this question: Why does a sky turn red when the evening comes?
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So... Rayleigh scattering

Here is a question about this article: In 1912, the Republic of China was established and Sun Yat-sen was inaugurated in Nanjing as the first Provisional President. But power in Beijing already had passed to Yuan Shikai, who had effective control of the Beiyang Army, the most powerful military force in China at the time. To prevent civil war and possible foreign intervention from undermining the infant republic, leaders agreed to Army's demand that China be united under a Beijing government. On March 10, in Beijing, Shikai was sworn in as the second Provisional President of the Republic of China.
What is the answer to this question: Who was sworn in as the second provisional president of the republic of China?
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So... Beijing, Shikai

Here is a question about this article: The southwest of the country is a coastal plain for which the primary drainage is the Kouilou-Niari River; the interior of the country consists of a central plateau between two basins to the south and north. Forests are under increasing exploitation pressure.
What is the answer to this question: Which river serves as drainage for the southwest plain of the Congo?
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So...
Kouilou-Niari River