Problem: YouTube:

YouTube is a global video-sharing website headquartered in San Bruno, California, United States. The service was created by three former PayPal employees in February 2005. In November 2006, it was bought by Google for US$1.65 billion. YouTube now operates as one of Google's subsidiaries. The site allows users to upload, view, rate, share, and comment on videos, and it makes use of WebM, H.264/MPEG-4 AVC, and Adobe Flash Video technology to display a wide variety of user-generated and corporate media video. Available content includes video clips, TV clips, music videos, movie trailers, and other content such as video blogging, short original videos, and educational videos.

What company did the three employees that started YouTube in 2006 used to work for?
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A: unanswerable

Problem: However, since the end of the Cold War, as the North Atlantic Treaty Organization (NATO) has moved much of its defence focus "out of area", the Canadian military has also become more deeply engaged in international security operations in various other parts of the world most notably in Afghanistan since 2002.
What country has the Canadian Military not worked in the last years?
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Answer: unanswerable

Q: What is a question about this article? If the question is unanswerable, say "unanswerable".
The formation of the ice giants, Neptune and Uranus, has proven difficult to model precisely. Current models suggest that the matter density in the outer regions of the Solar System was too low to account for the formation of such large bodies from the traditionally accepted method of core accretion, and various hypotheses have been advanced to explain their formation. One is that the ice giants were not formed by core accretion but from instabilities within the original protoplanetary disc and later had their atmospheres blasted away by radiation from a nearby massive OB star.
If Neptune wasn't formed from instabilities within the original protoplanetary disc, what was it formed by?
A: unanswerable

Context and question: Isaac Newton (16431727) inherited Descartes' mechanical conception of matter. In the third of his "Rules of Reasoning in Philosophy", Newton lists the universal qualities of matter as "extension, hardness, impenetrability, mobility, and inertia". Similarly in Optics he conjectures that God created matter as "solid, massy, hard, impenetrable, movable particles", which were "...even so very hard as never to wear or break in pieces". The "primary" properties of matter were amenable to mathematical description, unlike "secondary" qualities such as color or taste. Like Descartes, Newton rejected the essential nature of secondary qualities.
What did Descartes write?
Answer: unanswerable

Question: In June 2006, Steven Spielberg announced he would direct a scientifically accurate film about "a group of explorers who travel through a worm hole and into another dimension", from a treatment by Kip Thorne and producer Lynda Obst. In January 2007, screenwriter Jonathan Nolan met with them to discuss adapting Obst and Thorne's treatment into a narrative screenplay. The screenwriter suggested the addition of a "time element" to the treatment's basic idea, which was welcomed by Obst and Thorne. In March of that year, Paramount hired Nolan, as well as scientists from Caltech, forming a workshop to adapt the treatment under the title Interstellar. The following July, Kip Thorne said there was a push by people for him to portray himself in the film. Spielberg later abandoned Interstellar, which was eventually directed by Christopher Nolan.
Is there an answer to this question: In what year did Christopher Nolan become a director?

Answer: unanswerable

QUES: A common cause of software failure (real or perceived) is a lack of its compatibility with other application software, operating systems (or operating system versions, old or new), or target environments that differ greatly from the original (such as a terminal or GUI application intended to be run on the desktop now being required to become a web application, which must render in a web browser). For example, in the case of a lack of backward compatibility, this can occur because the programmers develop and test software only on the latest version of the target environment, which not all users may be running. This results in the unintended consequence that the latest work may not function on earlier versions of the target environment, or on older hardware that earlier versions of the target environment was capable of using. Sometimes such issues can be fixed by proactively abstracting operating system functionality into a separate program module or library.

What often lacks in software developed when its released that can eventually lead to errors?
What is the answer?
ANS:
a lack of backward compatibility