Problem: Alexander Graham Bell:

In 1870, at age 23, Bell, his brother's widow, Caroline (Margaret Ottaway), and his parents travelled on the SS Nestorian to Canada. After landing at Quebec City the Bells transferred to another steamer to Montreal and then boarded a train to Paris, Ontario, to stay with the Reverend Thomas Henderson, a family friend. After a brief stay with the Hendersons, the Bell family purchased a farm of 10.5 acres (42,000 m2) at Tutelo Heights (now called Tutela Heights), near Brantford, Ontario. The property consisted of an orchard, large farm house, stable, pigsty, hen-house, and a carriage house, which bordered the Grand River.[N 9]

How old was Bell when he went to Canada?
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A: 23


Problem: Dog:

Later genetic studies strongly supported dogs and gray wolves forming two sister monophyletic clades within the one species, and that the common ancestor of dogs and extant wolves is extinct.

The common relative of dogs and existing wolves is now considered what?
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A: extinct.


Problem: Estonian language:

The return of Soviet immigrants to their countries of origin has brought the proportion of Estonians in Estonia back above 70%. And again as in Latvia, today many of the remnant non-Estonians in Estonia have adopted the Estonian language; about 40% at the 2000 census.

What percentage of Estonians spoke Russian in 2000?
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A: unanswerable


Problem: Energy:

This law is a fundamental principle of physics. As shown rigorously by Noether's theorem, the conservation of energy is a mathematical consequence of translational symmetry of time, a property of most phenomena below the cosmic scale that makes them independent of their locations on the time coordinate. Put differently, yesterday, today, and tomorrow are physically indistinguishable. This is because energy is the quantity which is canonical conjugate to time. This mathematical entanglement of energy and time also results in the uncertainty principle - it is impossible to define the exact amount of energy during any definite time interval. The uncertainty principle should not be confused with energy conservation - rather it provides mathematical limits to which energy can in principle be defined and measured.

what should be confused with the uncertainty principle?
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A:
unanswerable