Problem: Treaty:

Articles 46–53 of the Vienna Convention on the Law of Treaties set out the only ways that treaties can be invalidated—considered unenforceable and void under international law. A treaty will be invalidated due to either the circumstances by which a state party joined the treaty, or due to the content of the treaty itself. Invalidation is separate from withdrawal, suspension, or termination (addressed above), which all involve an alteration in the consent of the parties of a previously valid treaty rather than the invalidation of that consent in the first place.

Which articles of the Vienna Convention on the Law of Treaties set out the ways that treaties can be invalidated?
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A: Articles 46–53


Problem: Orthodox Judaism:

Jewish historians also note that certain customs of today's Orthodox are not continuations of past practice, but instead represent innovations that would have been unknown to prior generations. For example, the now-widespread haredi tradition of cutting a boy's hair for the first time on his third birthday (upshirin or upsheerin, Yiddish for "haircut") "originated as an Arab custom that parents cut a newborn boy's hair and burned it in a fire as a sacrifice," and "Jews in Palestine learned this custom from Arabs and adapted it to a special Jewish context." The Ashkenazi prohibition against eating kitniyot (grains and legumes such as rice, corn, beans, and peanuts) during Passover was explicitly rejected in the Talmud, has no known precedent before the 12th century and represented a minority position for hundreds of years thereafter, but nonetheless has remained a mandatory prohibition among Ashkenazi Orthodox Jews due to their historic adherence to the ReMA's rulings in the Shulchan Aruch.

What do historians note are continuations of past practices?
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A: unanswerable


Problem: Airport:

Hazards to aircraft include debris, nesting birds, and reduced friction levels due to environmental conditions such as ice, snow, or rain. Part of runway maintenance is airfield rubber removal which helps maintain friction levels. The fields must be kept clear of debris using cleaning equipment so that loose material does not become a projectile and enter an engine duct (see foreign object damage). In adverse weather conditions, ice and snow clearing equipment can be used to improve traction on the landing strip. For waiting aircraft, equipment is used to spray special deicing fluids on the wings.

Why must the field be kept clear of nesting birds?
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A: unanswerable


Problem: States of Germany:

The use of the term Länder (Lands) dates back to the Weimar Constitution of 1919. Before this time, the constituent states of the German Empire were called Staaten (States). Today, it is very common to use the term Bundesland (Federal Land). However, this term is not used officially, neither by the constitution of 1919 nor by the Basic Law (Constitution) of 1949. Three Länder call themselves Freistaaten (Free States, which is the old-fashioned German expression for Republic), Bavaria (since 1919), Saxony (originally since 1919 and again since 1990), and Thuringia (since 1994). There is little continuity between the current states and their predecessors of the Weimar Republic with the exception of the three free states, and the two city-states of Hamburg and Bremen.

What year was the German Constitution written?
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A:
unanswerable