Problem: Extract the answer to the question from the following context. Question: What are vocal cords and mouths used for in the a capella world? Context: In addition to singing words, some a cappella singers also emulate instrumentation by reproducing instrumental sounds with their vocal cords and mouth. One of the earliest 20th century practitioners of this method were The Mills Brothers whose early recordings of the 1930s clearly stated on the label that all instrumentation was done vocally. More recently, "Twilight Zone" by 2 Unlimited was sung a cappella to the instrumentation on the comedy television series Tompkins Square. Another famous example of emulating instrumentation instead of singing the words is the theme song for The New Addams Family series on Fox Family Channel (now ABC Family). Groups such as Vocal Sampling and Undivided emulate Latin rhythms a cappella. In the 1960s, the Swingle Singers used their voices to emulate musical instruments to Baroque and Classical music. Vocal artist Bobby McFerrin is famous for his instrumental emulation. A cappella group Naturally Seven recreates entire songs using vocal tones for every instrument.

A: In addition to singing words, some a cappella singers also emulate instrumentation

Problem: Extract the answer to the question from the following context. Question: Which of the following is not fully equivalent: delegaciones, boroughs, or municipalities? Context: For administrative purposes, the Federal District is divided into 16 "delegaciones" or boroughs. While not fully equivalent to a municipality, the 16 boroughs have gained significant autonomy, and since 2000 their heads of government are elected directly by plurality (they were previously appointed by the head of government of the Federal District). Given that Mexico City is organized entirely as a Federal District, most of the city services are provided or organized by the Government of the Federal District and not by the boroughs themselves, while in the constituent states these services would be provided by the municipalities. The 16 boroughs of the Federal District with their 2010 populations are:

A: municipality

Problem: Extract the answer to the question from the following context. Question: What makes the kerosene easy to separate? Context: Asphalt/bitumen is typically stored and transported at temperatures around 150 C (302 F). Sometimes diesel oil or kerosene are mixed in before shipping to retain liquidity; upon delivery, these lighter materials are separated out of the mixture. This mixture is often called "bitumen feedstock", or BFS. Some dump trucks route the hot engine exhaust through pipes in the dump body to keep the material warm. The backs of tippers carrying asphalt/bitumen, as well as some handling equipment, are also commonly sprayed with a releasing agent before filling to aid release. Diesel oil is no longer used as a release agent due to environmental concerns.

A: lighter materials

Problem: Extract the answer to the question from the following context. Question: Who went to school in Chicago? Context: Hayek had made contact with many at the U. of Chicago in the 1940s, with Hayek's The Road to Serfdom playing a seminal role in transforming how Milton Friedman and others understood how society works. Hayek conducted a number in influential faculty seminars while at the U. of Chicago, and a number of academics worked on research projects sympathetic to some of Hayek's own, such as Aaron Director, who was active in the Chicago School in helping to fund and establish what became the "Law and Society" program in the University of Chicago Law School. Hayek, Frank Knight, Friedman and George Stigler worked together in forming the Mont Pelerin Society, an international forum for libertarian economists. Hayek and Friedman cooperated in support of the Intercollegiate Society of Individualists, later renamed the Intercollegiate Studies Institute, an American student organisation devoted to libertarian ideas.

A:
Hayek, Frank Knight, Friedman and George Stigler