Here is a question about this article: By 3400 BCE, the Sahara was as dry as it is today, due to reduced precipitation and higher temperatures resulting from a shift in the Earth's orbit. As a result of this aridification, it became a largely impenetrable barrier to humans, with the remaining settlements mainly being concentrated around the numerous oases that dot the landscape. Little trade or commerce is known to have passed through the interior in subsequent periods, the only major exception being the Nile Valley. The Nile, however, was impassable at several cataracts, making trade and contact by boat difficult.
What is the answer to this question: What area is known for having the majority of the trade?
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So... the Nile Valley

Here is a question about this article: In the last two decades, photovoltaics (PV), also known as solar PV, has evolved from a pure niche market of small scale applications towards becoming a mainstream electricity source. A solar cell is a device that converts light directly into electricity using the photoelectric effect. The first solar cell was constructed by Charles Fritts in the 1880s. In 1931 a German engineer, Dr Bruno Lange, developed a photo cell using silver selenide in place of copper oxide. Although the prototype selenium cells converted less than 1% of incident light into electricity, both Ernst Werner von Siemens and James Clerk Maxwell recognized the importance of this discovery. Following the work of Russell Ohl in the 1940s, researchers Gerald Pearson, Calvin Fuller and Daryl Chapin created the crystalline silicon solar cell in 1954. These early solar cells cost 286 USD/watt and reached efficiencies of 4.56%. By 2012 available efficiencies exceed 20% and the maximum efficiency of research photovoltaics is over 40%.
What is the answer to this question: Who created the crystalline silicon solar cell?
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So... Gerald Pearson, Calvin Fuller and Daryl Chapin

Here is a question about this article: One of the paper's best known front pages, published on 4 May 1982, commemorated the torpedoing of the Argentine ship the General Belgrano by running the story under the headline "GOTCHA". At MacKenzie's insistence, and against the wishes of Murdoch (the mogul was present because almost all the journalists were on strike), the headline was changed for later editions after the extent of Argentinian casualties became known. John Shirley, a reporter for The Sunday Times, witnessed copies of this edition of The Sun being thrown overboard by sailors and marines on HMS Fearless.
What is the answer to this question: Why did The Sun change the wording of the headline?
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So...
the extent of Argentinian casualties became known