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When a molten metal is mixed with another substance, there are two mechanisms that can cause an alloy to form, called atom exchange and the interstitial mechanism. The relative size of each element in the mix plays a primary role in determining which mechanism will occur. When the atoms are relatively similar in size, the atom exchange method usually happens, where some of the atoms composing the metallic crystals are substituted with atoms of the other constituent. This is called a substitutional alloy. Examples of substitutional alloys include bronze and brass, in which some of the copper atoms are substituted with either tin or zinc atoms. With the interstitial mechanism, one atom is usually much smaller than the other, so cannot successfully replace an atom in the crystals of the base metal. The smaller atoms become trapped in the spaces between the atoms in the crystal matrix, called the interstices. This is referred to as an interstitial alloy. Steel is an example of an interstitial alloy, because the very small carbon atoms fit into interstices of the iron matrix. Stainless steel is an example of a combination of interstitial and substitutional alloys, because the carbon atoms fit into the interstices, but some of the iron atoms are replaced with nickel and chromium atoms.
What is the name of one interstitial alloy?
A: Steel

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The influence of Old Norse certainly helped move English from a synthetic language along the continuum to a more analytic word order, and Old Norse most likely made a greater impact on the English language than any other language. The eagerness of Vikings in the Danelaw to communicate with their southern Anglo-Saxon neighbors produced a friction that led to the erosion of the complicated inflectional word-endings. Simeon Potter notes: "No less far-reaching was the influence of Scandinavian upon the inflexional endings of English in hastening that wearing away and leveling of grammatical forms which gradually spread from north to south. It was, after all, a salutary influence. The gain was greater than the loss. There was a gain in directness, in clarity, and in strength."
Why did the Vikings stop using complicated word-endings?
A: unanswerable

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Of the approximately 850 municipalities of Thuringia, 126 are classed as towns (within a district) or cities (forming their own urban district). Most of the towns are small with a population of less than 10,000; only the ten biggest ones have a population greater than 30,000. The first towns emerged during the 12th century, whereas the latest ones received town status only in the 20th century. Today, all municipalities within districts are equal in law, whether they are towns or villages. Independent cities (i.e. urban districts) have greater powers (the same as any district) than towns within a district.
How many municipalities in Thuringia are classified as hostile?
A: unanswerable

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In European history, the Middle Ages or medieval period lasted from the 5th to the 15th century. It began with the collapse of the Western Roman Empire and merged into the Renaissance and the Age of Discovery. The Middle Ages is the middle period of the three traditional divisions of Western history: Antiquity, Medieval period, and Modern period. The Medieval period is itself subdivided into the Early, the High, and the Late Middle Ages.
Along with the Renaissance, what era occurred at the end of the Middle Ages?
A:
Age of Discovery