Problem: On the Origin of Species:

On the Origin of Species, published on 24 November 1859, is a work of scientific literature by Charles Darwin which is considered to be the foundation of evolutionary biology. Darwin's book introduced the scientific theory that populations evolve over the course of generations through a process of natural selection. It presented a body of evidence that the diversity of life arose by common descent through a branching pattern of evolution. Darwin included evidence that he had gathered on the Beagle expedition in the 1830s and his subsequent findings from research, correspondence, and experimentation.

When was the Origin of Species published?
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A: 24 November 1859

Problem: In Canada, "the 51st state" is a phrase generally used in such a way as to imply that if a certain political course is taken, Canada's destiny will be as little more than a part of the United States. Examples include the Canada-United States Free Trade Agreement in 1988, the debate over the creation of a common defense perimeter, and as a potential consequence of not adopting proposals intended to resolve the issue of Quebec sovereignty, the Charlottetown Accord in 1992 and the Clarity Act in 1999.
When was the Charlottetown Accord signed?
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Answer: 1992

Q: What is a question about this article? If the question is unanswerable, say "unanswerable".
Czech contains ten basic vowel phonemes, and three more found only in loanwords. They are /a/, //, //, /o/, and /u/, their long counterparts /a/, //, /i/, /o/ and /u/, and three diphthongs, /ou/, /au/ and /u/. The latter two diphthongs and the long /o/ are exclusive to loanwords. Vowels are never reduced to schwa sounds when unstressed. Each word usually has primary stress on its first syllable, except for enclitics (minor, monosyllabic, unstressed syllables). In all words of more than two syllables, every odd-numbered syllable receives secondary stress. Stress is unrelated to vowel length, and the possibility of stressed short vowels and unstressed long vowels can be confusing to students whose native language combines the features (such as English).
What a few exceptions where is the primary word stress in Czech?
A: first syllable

Context and question: There are several reasons an otherwise valid and agreed upon treaty may be rejected as a binding international agreement, most of which involve problems created at the formation of the treaty.[citation needed] For example, the serial Japan-Korea treaties of 1905, 1907 and 1910 were protested; and they were confirmed as "already null and void" in the 1965 Treaty on Basic Relations between Japan and the Republic of Korea.
In what treaty were the serial Japan-Korea treaties of 1905, 1907, and 1910 confirmed as "already null and void?"
Answer: the 1965 Treaty on Basic Relations between Japan and the Republic of Korea

Question: Monroe's style involved playing lead melodies in the style of a fiddler, and also a percussive chording sound referred to as "the chop" for the sound made by the quickly struck and muted strings. He also perfected a sparse, percussive blues style, especially up the neck in keys that had not been used much in country music, notably B and E. He emphasized a powerful, syncopated right hand at the expense of left-hand virtuosity. Monroe's most influential follower of the second generation is Frank Wakefield and nowadays Mike Compton of the Nashville Bluegrass Band and David Long, who often tour as a duet. Tiny Moore of the Texas Playboys developed an electric five-string mandolin and helped popularize the instrument in Western Swing music.
Is there an answer to this question: What chording feeling was Monroe popular for?

Answer: unanswerable

Question: In the tree a knot is either the base of a side branch or a dormant bud. A knot (when the base of a side branch) is conical in shape (hence the roughly circular cross-section) with the inner tip at the point in stem diameter at which the plant's vascular cambium was located when the branch formed as a bud.
Is there an answer to this question: What measurement of a stem determines a knot's inner tip placement?

Answer:
diameter