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Free ISPs are Internet service providers that provide service free of charge. Many free ISPs display advertisements while the user is connected; like commercial television, in a sense they are selling the user's attention to the advertiser. Other free ISPs, sometimes called freenets, are run on a nonprofit basis, usually with volunteer staff.[citation needed]
What do free ISPs display in exchange for service?
A: advertisements

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As of the census of 2000, there are 84,084 people, 44,497 households, and 16,775 families in the city. The population density is 10,178.7 inhabitants per square mile (3,930.4/km²). There are 47,863 housing units at an average density of 5,794.0 per square mile (2,237.3/km²). The racial makeup of the city is 78.29% White, 7.25% Asian, 3.78% African American, 0.47% Native American, 0.10% Pacific Islander, 5.97% from other races, and 4.13% from two or more races. 13.44% of the population are Hispanic or Latino of any race. There are 44,497 households, out of which 15.8% have children under the age of 18, 27.5% are married couples living together, 7.5% have a female householder with no husband present, and 62.3% are non-families. 51.2% of all households are made up of individuals and 10.6% have someone living alone who is 65 years of age or older. The average household size is 1.83 and the average family size is 2.80.
What is the population density per square mile?
A: 10,178.7

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Season five began on January 17, 2006. It remains the highest-rated season in the show's run so far. Two of the more prominent contestants during the Hollywood round were the Brittenum twins who were later disqualified for identity theft.
Which season of American Idol stands out for having the highest ratings?
A: Season five

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Perhaps the most prominent, controversial and far-reaching theory in all of science has been the theory of evolution by natural selection put forward by the British naturalist Charles Darwin in his book On the Origin of Species in 1859. Darwin proposed that the features of all living things, including humans, were shaped by natural processes over long periods of time. The theory of evolution in its current form affects almost all areas of biology. Implications of evolution on fields outside of pure science have led to both opposition and support from different parts of society, and profoundly influenced the popular understanding of "man's place in the universe". In the early 20th century, the study of heredity became a major investigation after the rediscovery in 1900 of the laws of inheritance developed by the Moravian monk Gregor Mendel in 1866. Mendel's laws provided the beginnings of the study of genetics, which became a major field of research for both scientific and industrial research. By 1953, James D. Watson, Francis Crick and Maurice Wilkins clarified the basic structure of DNA, the genetic material for expressing life in all its forms. In the late 20th century, the possibilities of genetic engineering became practical for the first time, and a massive international effort began in 1990 to map out an entire human genome (the Human Genome Project).
What was the name of the book that Darwin wrote about evolution?
A:
On the Origin of Species