Problem: Extract the answer to the question from the following context. Question: what does DST do? Context: DST has mixed effects on health. In societies with fixed work schedules it provides more afternoon sunlight for outdoor exercise. It alters sunlight exposure; whether this is beneficial depends on one's location and daily schedule, as sunlight triggers vitamin D synthesis in the skin, but overexposure can lead to skin cancer. DST may help in depression by causing individuals to rise earlier, but some argue the reverse. The Retinitis Pigmentosa Foundation Fighting Blindness, chaired by blind sports magnate Gordon Gund, successfully lobbied in 1985 and 2005 for US DST extensions.

A: has mixed effects on health

Problem: Extract the answer to the question from the following context. Question: What is being generated? Context: According to a 2011 projection by the International Energy Agency, solar power plants may produce most of the world's electricity within 50 years, significantly reducing the emissions of greenhouse gases that harm the environment. The IEA has said: "Photovoltaic and solar-thermal plants may meet most of the world's demand for electricity by 2060 and half of all energy needs with wind, hydropower and biomass plants supplying much of the remaining generation". "Photovoltaic and concentrated solar power together can become the major source of electricity".

A: electricity

Problem: Extract the answer to the question from the following context. Question: What is often the main usage of the passage's topic? Context: In spite of their flaws, such as the lack of portability, records still have enthusiastic supporters. Vinyl records continue to be manufactured and sold today, especially by independent rock bands and labels, although record sales are considered to be a niche market composed of audiophiles, collectors, and DJs. Old records and out-of-print recordings in particular are in much demand by collectors the world over. (See Record collecting.) Many popular new albums are given releases on vinyl records and older albums are also given reissues, sometimes on audiophile-grade vinyl.

A: Many popular new albums are given releases on vinyl records and older albums are also given reissues, sometimes on audiophile-grade vinyl

Problem: Extract the answer to the question from the following context. Question: Which happened before 1971, Heitaro Nakajima developed an early digital audio recorder or his team developed a digital PCM adaptor audio tape recorder? Context: Heitaro Nakajima, who developed an early digital audio recorder within Japan's national public broadcasting organization NHK in 1970, became general manager of Sony's audio department in 1971. His team developed a digital PCM adaptor audio tape recorder using a Betamax video recorder in 1973. After this, in 1974 the leap to storing digital audio on an optical disc was easily made. Sony first publicly demonstrated an optical digital audio disc in September 1976. A year later, in September 1977, Sony showed the press a 30 cm disc that could play 60 minutes of digital audio (44,100 Hz sampling rate and 16-bit resolution) using MFM modulation. In September 1978, the company demonstrated an optical digital audio disc with a 150-minute playing time, 44,056 Hz sampling rate, 16-bit linear resolution, and cross-interleaved error correction codespecifications similar to those later settled upon for the standard Compact Disc format in 1980. Technical details of Sony's digital audio disc were presented during the 62nd AES Convention, held on 1316 March 1979, in Brussels. Sony's AES technical paper was published on 1 March 1979. A week later, on 8 March, Philips publicly demonstrated a prototype of an optical digital audio disc at a press conference called "Philips Introduce Compact Disc" in Eindhoven, Netherlands.

A:
developed an early digital audio recorder