Problem: The energy levels of hydrogen can be calculated fairly accurately using the Bohr model of the atom, which conceptualizes the electron as "orbiting" the proton in analogy to the Earth's orbit of the Sun. However, the electromagnetic force attracts electrons and protons to one another, while planets and celestial objects are attracted to each other by gravity. Because of the discretization of angular momentum postulated in early quantum mechanics by Bohr, the electron in the Bohr model can only occupy certain allowed distances from the proton, and therefore only certain allowed energies.
What attracts planets and celestial items?
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Answer: gravity

Problem: There is a sizable Somali community in the United Arab Emirates. Somali-owned businesses line the streets of Deira, the Dubai city centre, with only Iranians exporting more products from the city at large. Internet cafes, hotels, coffee shops, restaurants and import-export businesses are all testimony to the Somalis' entrepreneurial spirit. Star African Air is also one of three Somali-owned airlines which are based in Dubai.
What is another name for the city center of Dubai?
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Answer: Deira

Problem: Santa Monica is a beachfront city in western Los Angeles County, California, United States. The city is named after the Christian saint, Monica. Situated on Santa Monica Bay, it is bordered on three sides by the city of Los Angeles Pacific Palisades to the north, Brentwood on the northeast, Sawtelle on the east, Mar Vista on the southeast, and Venice on the south. Santa Monica is well known for its affluent single-family neighborhoods but also has many neighborhoods consisting primarily of condominiums and apartments. Over two-thirds of Santa Monica's residents are renters. The Census Bureau population for Santa Monica in 2010 was 89,736.
How many condominiums are there in Santa Monica?
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Answer:
unanswerable