instruction:
This task is about writing a correct answer for the reading comprehension task. Based on the information provided in a given passage, you should identify the shortest continuous text span from the passage that serves as an answer to the given question. Avoid answers that are incorrect or provides incomplete justification for the question.
question:
Passage: Old English was not static, and its usage covered a period of 700 years, from the Anglo-Saxon settlement of Britain in the 5th century to the late 11th century, some time after the Norman invasion. While indicating that the establishment of dates is an arbitrary process, Albert Baugh dates Old English from 450 to 1150, a period of full inflections, a synthetic language. Perhaps around 85 per cent of Old English words are no longer in use, but those that survived, to be sure, are basic elements of Modern English vocabulary. Question: In what century did Old English cease to be used?
answer:
11th

question:
Passage: The gut is generally an almost straight tube supported by the mesenteries (vertical partitions within segments), and ends with the anus on the underside of the pygidium. However, in members of the tube-dwelling family Siboglinidae the gut is blocked by a swollen lining that houses symbiotic bacteria, which can make up 15% of the worms' total weight. The bacteria convert inorganic matter such as hydrogen sulfide and carbon dioxide from hydrothermal vents, or methane from seeps to organic matter that feeds themselves and their hosts, while the worms extend their palps into the gas flows to absorb the gases needed by the bacteria. Question: How much of a Siboglinidae's weight is symbiotic bacteria?
answer:
15%

question:
Passage: Alpine symbolism has played an essential role in shaping the history of the country and the Swiss national identity. Nowadays some concentrated mountain areas have a strong highly energetic ski resort culture in winter, and a hiking (ger: das Wandern) or Mountain biking culture in summer. Other areas throughout the year have a recreational culture that caters to tourism, yet the quieter seasons are spring and autumn when there are fewer visitors. A traditional farmer and herder culture also predominates in many areas and small farms are omnipresent outside the cities. Folk art is kept alive in organisations all over the country. In Switzerland it is mostly expressed in music, dance, poetry, wood carving and embroidery. The alphorn, a trumpet-like musical instrument made of wood, has become alongside yodeling and the accordion an epitome of traditional Swiss music. Question: What is the name of the trumpet like musical instrument made of wood has become the epitome of traditional Swiss music?
answer:
alphorn