Here is a question about this article: In the second half of '90s, MP3 files began to spread on the Internet. The popularity of MP3s began to rise rapidly with the advent of Nullsoft's audio player Winamp, released in 1997. In 1998, the first portable solid state digital audio player MPMan, developed by SaeHan Information Systems which is headquartered in Seoul, South Korea, was released and the Rio PMP300 was sold afterwards in 1998, despite legal suppression efforts by the RIAA.
What is the answer to this question: What was the name of the first portable solid state digital audio player?
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So... MPMan

Here is a question about this article: Consent will also be invalidated if it was induced by the fraudulent conduct of another party, or by the direct or indirect "corruption" of its representative by another party to the treaty. Coercion of either a representative, or the state itself through the threat or use of force, if used to obtain the consent of that state to a treaty, will invalidate that consent.
What is the answer to this question: What must be true of coercion through the threat or use of force of a party to treaty for it to invalidate the state's consent to a treaty?
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So... used to obtain the consent of that state to a treaty

Here is a question about this article: The rise of port cities saw the clustering of populations caused by the development of steamships and railroads. Urbanization increased from 1700 to 1922, with towns and cities growing. Improvements in health and sanitation made them more attractive to live and work in. Port cities like Salonica, in Greece, saw its population rise from 55,000 in 1800 to 160,000 in 1912 and Izmir which had a population of 150,000 in 1800 grew to 300,000 by 1914. Some regions conversely had population falls Belgrade saw its population drop from 25,000 to 8,000 mainly due to political strife.
What is the answer to this question: The rise of ports caused what in populations?
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So...
the clustering of populations