Problem: Late Middle Ages:

The period saw several important technical innovations, like the principle of linear perspective found in the work of Masaccio, and later described by Brunelleschi. Greater realism was also achieved through the scientific study of anatomy, championed by artists like Donatello. This can be seen particularly well in his sculptures, inspired by the study of classical models. As the centre of the movement shifted to Rome, the period culminated in the High Renaissance masters da Vinci, Michelangelo and Raphael.

Along with da Vinci, who were two other artists regarded as masters of the High Renaissance?
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A: Michelangelo and Raphael

Problem: The relative peace of the Tokugawa era was shattered with the arrival of Commodore Matthew Perry's massive U.S. Navy steamships in 1853. Perry used his superior firepower to force Japan to open its borders to trade. Prior to that only a few harbor towns, under strict control from the Shogunate, were allowed to participate in Western trade, and even then, it was based largely on the idea of playing the Franciscans and Dominicans off against one another (in exchange for the crucial arquebus technology, which in turn was a major contributor to the downfall of the classical samurai).
Which force invaded Japan in 1853?
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Answer: U.S. Navy

Q: What is a question about this article? If the question is unanswerable, say "unanswerable".
Extending the Gregorian calendar backwards to dates preceding its official introduction produces a proleptic calendar, which should be used with some caution. For ordinary purposes, the dates of events occurring prior to 15 October 1582 are generally shown as they appeared in the Julian calendar, with the year starting on 1 January, and no conversion to their Gregorian equivalents. For example, the Battle of Agincourt is universally considered to have been fought on 25 October 1415 which is Saint Crispin's Day.
What can you extend backwards to create an accurate calendar?
A: unanswerable

Context and question: Compression efficiency of encoders is typically defined by the bit rate, because compression ratio depends on the bit depth and sampling rate of the input signal. Nevertheless, compression ratios are often published. They may use the Compact Disc (CD) parameters as references (44.1 kHz, 2 channels at 16 bits per channel or 216 bit), or sometimes the Digital Audio Tape (DAT) SP parameters (48 kHz, 216 bit). Compression ratios with this latter reference are higher, which demonstrates the problem with use of the term compression ratio for lossy encoders.
What can CD parameters be used as references for?
Answer: compression ratios

Question: Early humanists saw no conflict between reason and their Christian faith (see Christian Humanism). They inveighed against the abuses of the Church, but not against the Church itself, much less against religion. For them, the word "secular" carried no connotations of disbelief that would come later, in the nineteenth century. In the Renaissance to be secular meant simply to be in the world rather than in a monastery. Petrarch frequently admitted that his brother Gherardo's life as a Carthusian monk was superior to his own (although Petrarch himself was in Minor Orders and was employed by the Church all his life). He hoped that he could do some good by winning earthly glory and praising virtue, inferior though that might be to a life devoted solely to prayer. By embracing a non-theistic philosophic base, however, the methods of the humanists, combined with their eloquence, would ultimately have a corrosive effect on established authority.
Is there an answer to this question: Petrarch felt that although he tried to do his own form of good whose life may have more meaning?

Answer: Gherardo

Question: The top 50 m (160 ft) of a glacier are rigid because they are under low pressure. This upper section is known as the fracture zone and moves mostly as a single unit over the plastically flowing lower section. When a glacier moves through irregular terrain, cracks called crevasses develop in the fracture zone. Crevasses form due to differences in glacier velocity. If two rigid sections of a glacier move at different speeds and directions, shear forces cause them to break apart, opening a crevasse. Crevasses are seldom more than 46 m (150 ft) deep but in some cases can be 300 m (1,000 ft) or even deeper. Beneath this point, the plasticity of the ice is too great for cracks to form. Intersecting crevasses can create isolated peaks in the ice, called seracs.
Is there an answer to this question: What is the free flowing upper section known as?

Answer:
unanswerable