Answer the question from the given passage. Your answer should be directly extracted from the passage, and it should be a single entity, name, or number, not a sentence.

Q: Passage: Oxygen was discovered independently by Carl Wilhelm Scheele, in Uppsala, in 1773 or earlier, and Joseph Priestley in Wiltshire, in 1774, but Priestley is often given priority because his work was published first. The name oxygen was coined in 1777 by Antoine Lavoisier, whose experiments with oxygen helped to discredit the then-popular phlogiston theory of combustion and corrosion. Its name derives from the Greek roots ὀξύς oxys, 'acid', literally 'sharp', referring to the sour taste of acids and -γενής -genes, 'producer', literally 'begetter', because at the time of naming, it was mistakenly thought that all acids required oxygen in their composition. Common uses of oxygen includes the production cycle of steel, plastics and textiles, brazing, welding and cutting of steels and other metals, rocket propellant, in oxygen therapy and life support systems in aircraft, submarines, spaceflight and diving. Question: What previous work did Lavoisier experiments discredit?

A: phlogiston theory of combustion and corrosion
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Q: Passage: The V&A has its origins in the Great Exhibition of 1851, with which Henry Cole, the museum's first director, was involved in planning; initially it was known as the Museum of Manufactures, first opening in May 1852 at Marlborough House, but by September had been transferred to Somerset House. At this stage the collections covered both applied art and science. Several of the exhibits from the Exhibition were purchased to form the nucleus of the collection. By February 1854 discussions were underway to transfer the museum to the current site and it was renamed South Kensington Museum. In 1855 the German architect Gottfried Semper, at the request of Cole, produced a design for the museum, but it was rejected by the Board of Trade as too expensive. The site was occupied by Brompton Park House; this was extended including the first refreshment rooms opened in 1857, the museum being the first in the world to provide such a facility. Question: Which German architect was asked to produce a design for the museum?

A: Gottfried Semper
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Q: Passage: Six-time Grammy winner and Academy Award nominee Lady Gaga performed the national anthem, while Academy Award winner Marlee Matlin provided American Sign Language (ASL) translation. Question: Who did the Super Bowl 50 National Anthem?

A:
Lady Gaga
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