Problem: Copper:

Most copper is mined or extracted as copper sulfides from large open pit mines in porphyry copper deposits that contain 0.4 to 1.0% copper. Examples include Chuquicamata in Chile, Bingham Canyon Mine in Utah, United States and El Chino Mine in New Mexico, United States. According to the British Geological Survey, in 2005, Chile was the top mine producer of copper with at least one-third world share followed by the United States, Indonesia and Peru. Copper can also be recovered through the in-situ leach process. Several sites in the state of Arizona are considered prime candidates for this method. The amount of copper in use is increasing and the quantity available is barely sufficient to allow all countries to reach developed world levels of usage.

What percentage of mercury do the deposits have that are extracted?
---
A: unanswerable


Problem: Pesticide:

The first legislation providing federal authority for regulating pesticides was enacted in 1910; however, decades later during the 1940s manufacturers began to produce large amounts of synthetic pesticides and their use became widespread. Some sources consider the 1940s and 1950s to have been the start of the "pesticide era." Although the U.S. Environmental Protection Agency was established in 1970 and amendments to the pesticide law in 1972, pesticide use has increased 50-fold since 1950 and 2.3 million tonnes (2.5 million short tons) of industrial pesticides are now[when?] used each year. Seventy-five percent of all pesticides in the world are used in developed countries, but use in developing countries is increasing. A study of USA pesticide use trends through 1997 was published in 2003 by the National Science Foundation's Center for Integrated Pest Management.

What is 1910 considered the start of according to some sources?
---
A: unanswerable


Problem: A cappella:

In July 1943, as a result of the American Federation of Musicians boycott of US recording studios, the a cappella vocal group The Song Spinners had a best-seller with "Comin' In On A Wing And A Prayer". In the 1950s several recording groups, notably The Hi-Los and the Four Freshmen, introduced complex jazz harmonies to a cappella performances. The King's Singers are credited with promoting interest in small-group a cappella performances in the 1960s. In 1983 an a cappella group known as The Flying Pickets had a Christmas 'number one' in the UK with a cover of Yazoo's (known in the US as Yaz) "Only You". A cappella music attained renewed prominence from the late 1980s onward, spurred by the success of Top 40 recordings by artists such as The Manhattan Transfer, Bobby McFerrin, Huey Lewis and the News, All-4-One, The Nylons, Backstreet Boys and Boyz II Men.[citation needed]

In 1983 what did The King's Singers promote?
---
A: unanswerable


Problem: Antibiotics:

Florey and Chain succeeded in purifying the first penicillin, penicillin G, in 1942, but it did not become widely available outside the Allied military before 1945. Later, Norman Heatley developed the back extraction technique for efficiently purifying penicillin in bulk. The chemical structure of penicillin was determined by Dorothy Crowfoot Hodgkin in 1945. Purified penicillin displayed potent antibacterial activity against a wide range of bacteria and had low toxicity in humans. Furthermore, its activity was not inhibited by biological constituents such as pus, unlike the synthetic sulfonamides. The discovery of such a powerful antibiotic was unprecedented, and the development of penicillin led to renewed interest in the search for antibiotic compounds with similar efficacy and safety. For their successful development of penicillin, which Fleming had accidentally discovered but could not develop himself, as a therapeutic drug, Ernst Chain and Howard Florey shared the 1945 Nobel Prize in Medicine with Fleming. Florey credited Dubos with pioneering the approach of deliberately and systematically searching for antibacterial compounds, which had led to the discovery of gramicidin and had revived Florey's research in penicillin.

When did penicillin G become available as a therapeudic drug?
---
A:
unanswerable