Problem: John von Neumann:

The second approach to the problem took as its base the notion of class, and defines a set as a class which belongs to other classes, while a proper class is defined as a class which does not belong to other classes. Under the Zermelo–Fraenkel approach, the axioms impede the construction of a set of all sets which do not belong to themselves. In contrast, under the von Neumann approach, the class of all sets which do not belong to themselves can be constructed, but it is a proper class and not a set.

Under what approach does an axiom impede a set of all sets which do not belong to themselves?
---
A: Zermelo–Fraenkel


Problem: A study published in the Neuropsychopharmacology journal in 2013 revealed the finding that the flavour of beer alone could provoke dopamine activity in the brain of the male participants, who wanted to drink more as a result. The 49 men in the study were subject to positron emission tomography scans, while a computer-controlled device sprayed minute amounts of beer, water and a sports drink onto their tongues. Compared with the taste of the sports drink, the taste of beer significantly increased the participants desire to drink. Test results indicated that the flavour of the beer triggered a dopamine release, even though alcohol content in the spray was insufficient for the purpose of becoming intoxicated.
What did a 2031 study reveal?
---
Answer: unanswerable


Q: What is a question about this article? If the question is unanswerable, say "unanswerable".
Clinical immunology is the study of diseases caused by disorders of the immune system (failure, aberrant action, and malignant growth of the cellular elements of the system). It also involves diseases of other systems, where immune reactions play a part in the pathology and clinical features.
What are three problems of the immune system studied by clinical immunology?
A: failure, aberrant action, and malignant growth


Context and question: In a nationally televised speech early in the morning of December 25, 1991, Gorbachev resigned as president of the USSR – or, as he put it, "I hereby discontinue my activities at the post of President of the Union of Soviet Socialist Republics." He declared the office extinct, and all of its powers (such as control of the nuclear arsenal) were ceded to Yeltsin. A week earlier, Gorbachev had met with Yeltsin and accepted the fait accompli of the Soviet Union's dissolution. On the same day, the Supreme Soviet of the Russian SFSR adopted a statute to change Russia's legal name from "Russian Soviet Federative Socialist Republic" to "Russian Federation," showing that it was now a sovereign state.
Who was given control after Gorbachev left?
Answer: Yeltsin


Question: Bell's father, grandfather, and brother had all been associated with work on elocution and speech, and both his mother and wife were deaf, profoundly influencing Bell's life's work. His research on hearing and speech further led him to experiment with hearing devices which eventually culminated in Bell being awarded the first U.S. patent for the telephone in 1876.[N 4] Bell considered his most famous invention an intrusion on his real work as a scientist and refused to have a telephone in his study.[N 5]
Is there an answer to this question: What year did Bell get the patent for his telephone?

Answer: 1876


Problem: Spanish language in the United States:

Immigration to the United States of Spanish-speaking Cubans began because of Cuba's political instability upon achieving independence. The deposition of Fulgencio Batista's dictatorship and the ascension of Fidel Castro's government in 1959 increased Cuban immigration to the United States, hence there are some one million Cubans in the United States, most settled in southern and central Florida, while other Cubans live in the Northeastern United States; most are fluent in Spanish. In the city of Miami today Spanish is the first language mostly due to Cuban immigration.

What year did most Cubans start coming to America?
---
A:
The deposition of Fulgencio Batista's dictatorship and the ascension of Fidel Castro's government in 1959 increased Cuban immigration to the United States