This task is about creating an unanswerable question based on a given passage. Construct a question that looks relevant to the given context but is unanswerable. Following are a few suggestions about how to create unanswerable questions:
(i) create questions which require satisfying a constraint that is not mentioned in the passage
(ii) create questions which require information beyond what is provided in the passage in order to answer
(iii) replace an existing entity, number, date mentioned in the passage with other entity, number, date and use it in the question
(iv) create a question which is answerable from the passage and then replace one or two words by their antonyms or insert/remove negation words to make it unanswerable.

Q: Passage: Before the actual research explicitly devoted to the complexity of algorithmic problems started off, numerous foundations were laid out by various researchers. Most influential among these was the definition of Turing machines by Alan Turing in 1936, which turned out to be a very robust and flexible simplification of a computer.

A: What were laid out by various companies?
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Q: Passage: Where every component state of a federation possesses the same powers, we are said to find 'symmetric federalism'. Asymmetric federalism exists where states are granted different powers, or some possess greater autonomy than others do. This is often done in recognition of the existence of a distinct culture in a particular region or regions. In Spain, the Basques and Catalans, as well as the Galicians, spearheaded a historic movement to have their national specificity recognized, crystallizing in the "historical communities" such as Navarre, Galicia, Catalonia, and the Basque Country. They have more powers than the later expanded arrangement for other Spanish regions, or the Spain of the autonomous communities (called also the "coffee for everyone" arrangement), partly to deal with their separate identity and to appease peripheral nationalist leanings, partly out of respect to specific rights they had held earlier in history. However, strictly speaking Spain is not a federalism, but a decentralized administrative organization of the state.

A: What does no components state of federation possess?
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Q: Passage: Uranium-235 was the first isotope that was found to be fissile. Other naturally occurring isotopes are fissionable, but not fissile. On bombardment with slow neutrons, its uranium-235 isotope will most of the time divide into two smaller nuclei, releasing nuclear binding energy and more neutrons. If too many of these neutrons are absorbed by other uranium-235 nuclei, a nuclear chain reaction occurs that results in a burst of heat or (in special circumstances) an explosion. In a nuclear reactor, such a chain reaction is slowed and controlled by a neutron poison, absorbing some of the free neutrons. Such neutron absorbent materials are often part of reactor control rods (see nuclear reactor physics for a description of this process of reactor control).

A:
What isotope of uranium was the last to be found fissile?
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