Question: Up until the mid-14th century, Europe had experienced steadily increasing urbanisation. Cities were also decimated by the Black Death, but the role of urban areas as centres of learning, commerce and government ensured continued growth. By 1500, Venice, Milan, Naples, Paris and Constantinople each probably had more than 100,000 inhabitants. Twenty-two other cities were larger than 40,000; most of these were in Italy and the Iberian peninsula, but there were also some in France, the Empire, the Low Countries, plus London in England.
Is there an answer to this question: How many other cities had populations larger than 40,000 by 1600?

Answer: unanswerable


Question: The net quality of a ground reflection depends on the topography of the surface. When the irregularities of the surface are much smaller than the wavelength, we are in the regime of specular reflection, and the receiver sees both the real antenna and an image of the antenna under the ground due to reflection. But if the ground has irregularities not small compared to the wavelength, reflections will not be coherent but shifted by random phases. With shorter wavelengths (higher frequencies), this is generally the case.
Is there an answer to this question: What is the reason for the receiver seeing both the ral antenna and image of the antenna?

Answer: reflection


Question: Corporations and legislatures take different types of preventative measures to deter copyright infringement, with much of the focus since the early 1990s being on preventing or reducing digital methods of infringement. Strategies include education, civil & criminal legislation, and international agreements, as well as publicizing anti-piracy litigation successes and imposing forms of digital media copy protection, such as controversial DRM technology and anti-circumvention laws, which limit the amount of control consumers have over the use of products and content they have purchased.
Is there an answer to this question: What does DRM and anti-circumvention laws do?

Answer: limit the amount of control consumers have


Question: The Quine-Duhem thesis argues that it's impossible to test a single hypothesis on its own, since each one comes as part of an environment of theories. Thus we can only say that the whole package of relevant theories has been collectively falsified, but cannot conclusively say which element of the package must be replaced. An example of this is given by the discovery of the planet Neptune: when the motion of Uranus was found not to match the predictions of Newton's laws, the theory "There are seven planets in the solar system" was rejected, and not Newton's laws themselves. Popper discussed this critique of naïve falsificationism in Chapters 3 and 4 of The Logic of Scientific Discovery. For Popper, theories are accepted or rejected via a sort of selection process. Theories that say more about the way things appear are to be preferred over those that do not; the more generally applicable a theory is, the greater its value. Thus Newton's laws, with their wide general application, are to be preferred over the much more specific "the solar system has seven planets".[dubious – discuss]
Is there an answer to this question: What thesis says a scientific hypothesis is not testable in isolation from its system of theories?

Answer:
Quine-Duhem