Determine the topic of the question-answer pair. Question: "what is vitamin b12 used for?"; Answer: "Vitamin B12, vitamin B12 or vitamin B-12, also called cobalamin, is a water-soluble vitamin with a key role in the normal functioning of the brain and nervous system , and for the formation of blood ."? Topic:
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Answer: Vitamin B12

Q: Determine the topic of the question-answer pair. Question: "who is the actor that plays harry potter?"; Answer: "Daniel Radcliffe , who portrays Harry Potter , has been the icon of the film series since the release of the first film in 2001."? Topic:
A: List of Harry Potter cast members

Question: Determine the topic of the question-answer pair. Question: "what is the gdp for greenland 2010??"; Answer: "GDP per capita is similar to the average European economies but the economy is critically dependent upon substantial support from the Danish government, which supplies about half the revenues of the home rule government who in turn employ about 8,000 Greenlanders out of a labor force of 40,156 (Jan. 2012)."? Topic:
Answer: Economy of Greenland

[Q]: Determine the topic of the question-answer pair. Question: "what is middle class in the us?"; Answer: "Depending on class model used, the middle class may constitute anywhere from 25% to 66% of households."? Topic:
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[A]: American middle class

input: Please answer the following: Determine the topic of the question-answer pair. Question: "What does the idea of effective nuclear charge tell us?"; Answer: "The term "effective" is used because the shielding effect of negatively charged electrons prevents higher orbital electrons from experiencing the full nuclear charge by the repelling effect of inner-layer electrons."? Topic:
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output: Effective nuclear charge

Determine the topic of the question-answer pair. Question: "what it takes aerosmith album?"; Answer: "It was released in 1990 as the third single from Aerosmith's critically and commercially successful 1989 album Pump ."? Topic:
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Answer:
What It Takes (song)