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Replacing the classical physics in use since the end of the scientific revolution, modern physics arose in the early 20th century with the advent of quantum physics, substituting mathematical studies for experimental studies and examining equations to build a theoretical structure.[citation needed] The old quantum theory was a collection of results which predate modern quantum mechanics, but were never complete or self-consistent. The collection of heuristic prescriptions for quantum mechanics were the first corrections to classical mechanics. Outside the realm of quantum physics, the various aether theories in classical physics, which supposed a "fifth element" such as the Luminiferous aether, were nullified by the Michelson-Morley experiment—an attempt to detect the motion of earth through the aether. In biology, Darwinism gained acceptance, promoting the concept of adaptation in the theory of natural selection. The fields of geology, astronomy and psychology also made strides and gained new insights. In medicine, there were advances in medical theory and treatments.
The "fifth element" was disproved by what?
A: Michelson-Morley experiment

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Built around 1915, the Alaska Railroad (ARR) played a key role in the development of Alaska through the 20th century. It links north Pacific shipping through providing critical infrastructure with tracks that run from Seward to Interior Alaska by way of South Central Alaska, passing through Anchorage, Eklutna, Wasilla, Talkeetna, Denali, and Fairbanks, with spurs to Whittier, Palmer and North Pole. The cities, towns, villages, and region served by ARR tracks are known statewide as "The Railbelt". In recent years, the ever-improving paved highway system began to eclipse the railroad's importance in Alaska's economy.
To what does "The Railbelt" refer?
A: region served by ARR tracks

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Animals are generally considered to have evolved from a flagellated eukaryote. Their closest known living relatives are the choanoflagellates, collared flagellates that have a morphology similar to the choanocytes of certain sponges. Molecular studies place animals in a supergroup called the opisthokonts, which also include the choanoflagellates, fungi and a few small parasitic protists. The name comes from the posterior location of the flagellum in motile cells, such as most animal spermatozoa, whereas other eukaryotes tend to have anterior flagella.
Where does the name opisthokonts come from?
A: the posterior location of the flagellum in motile cells

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Some of the cleaner energy facilities in Boston include the Allston green district, with three ecologically compatible housing facilities. Boston is also breaking ground on multiple green affordable housing facilities to help reduce the carbon footprint of the city while simultaneously making these initiatives financially available to a greater population. Boston's climate plan is updated every three years and was most recently modified in 2013. This legislature includes the Building Energy Reporting and Disclosure Ordinance, which requires the city's larger buildings to disclose their yearly energy and water use statistics and partake in an energy assessment every five years. These statistics are made public by the city, thereby increasing incentives for buildings to be more environmentally conscious.
How often is Boston's climate plan updated?
A:
every three years