Input: Read this: Returning home to Brantford after six months abroad, Bell continued his experiments with his "harmonic telegraph".[N 12] The basic concept behind his device was that messages could be sent through a single wire if each message was transmitted at a different pitch, but work on both the transmitter and receiver was needed.
Question: For his system to work, Bell had to change what about each code?

Output: pitch

Input: Read this: The Jamahiriya's radical direction earned the government many enemies. In February 1978, Gaddafi discovered that his head of military intelligence was plotting to kill him, and began to increasingly entrust security to his Qaddadfa tribe. Many who had seen their wealth and property confiscated turned against the administration, and a number of western-funded opposition groups were founded by exiles. Most prominent was the National Front for the Salvation of Libya (NFSL), founded in 1981 by Mohammed Magariaf, which orchestrated militant attacks against Libya's government, while another, al-Borkan, began killing Libyan diplomats abroad. Following Gaddafi's command to kill these "stray dogs", under Colonel Younis Bilgasim's leadership, the Revolutionary Committees set up overseas branches to suppress counter-revolutionary activity, assassinating various dissidents. Although nearby nations like Syria also used hit squads, Gaddafi was unusual in publicly bragging about his administration's use of them; in June 1980, he ordered all dissidents to return home or be "liquidated wherever you are."
Question: What tribe did Gaddafi belong to?

Output: Qaddadfa

Input: Read this: Denial of service attacks are designed to make a machine or network resource unavailable to its intended users. Attackers can deny service to individual victims, such as by deliberately entering a wrong password enough consecutive times to cause the victim account to be locked, or they may overload the capabilities of a machine or network and block all users at once. While a network attack from a single IP address can be blocked by adding a new firewall rule, many forms of Distributed denial of service (DDoS) attacks are possible, where the attack comes from a large number of points and defending is much more difficult. Such attacks can originate from the zombie computers of a botnet, but a range of other techniques are possible including reflection and amplification attacks, where innocent systems are fooled into sending traffic to the victim.
Question: What is done to a password to lock out all users at once?

Output: unanswerable

Input: Read this: The Census Bureau's 20062010 American Community Survey showed that (in 2010 inflation-adjusted dollars) median household income was $30,237 (with a margin of error of +/- $2,354) and the median family income was $35,488 (+/- $2,607). Males had a median income of $32,207 (+/- $1,641) versus $29,298 (+/- $1,380) for females. The per capita income for the city was $20,069 (+/- $2,532). About 23.1% of families and 25.3% of the population were below the poverty line, including 36.6% of those under age 18 and 16.8% of those age 65 or over.
Question: How much was the median household income according to the American Community Survey?

Output:
$30,237