instruction:
In this task, you are given a question and a context passage. You have to answer the question based on the given passage.
question:
What is a prerequisite for weight to play a factor in conductivity?, Context: While inert gas reduces filament evaporation, it also conducts heat from the filament, thereby cooling the filament and reducing efficiency. At constant pressure and temperature, the thermal conductivity of a gas depends upon the molecular weight of the gas and the cross sectional area of the gas molecules. Higher molecular weight gasses have lower thermal conductivity, because both the molecular weight is higher and also the cross sectional area is higher. Xenon gas improves efficiency because of its high molecular weight, but is also more expensive, so its use is limited to smaller lamps.
answer:
constant pressure and temperature


question:
What was the aftermath?, Context: In June 1963, Rev. Martin Luther King, Jr. gave a major speech in Detroit that foreshadowed his "I Have a Dream" speech in Washington, D.C. two months later. While the African-American Civil Rights Movement gained significant federal civil rights laws in 1964 and 1965, longstanding inequities resulted in confrontations between the police and inner city black youth wanting change. Longstanding tensions in Detroit culminated in the Twelfth Street riot in July 1967. Governor George W. Romney ordered the Michigan National Guard into Detroit, and President Johnson sent in U.S. Army troops. The result was 43 dead, 467 injured, over 7,200 arrests, and more than 2,000 buildings destroyed, mostly in black residential and business areas. Thousands of small businesses closed permanently or relocated to safer neighborhoods. The affected district lay in ruins for decades. It was the most costly riot in the United States.
answer:
The result was 43 dead, 467 injured, over 7,200 arrests, and more than 2,000 buildings destroyed, mostly in black residential and business areas. Thousands of small businesses closed permanently or relocated to safer neighborhoods. The affected district lay in ruins for decades


question:
what are the first machines mentioned?, Context: The Japanese launch was followed in March 1983 by the introduction of CD players and discs to Europe and North America (where CBS Records released sixteen titles). This event is often seen as the "Big Bang" of the digital audio revolution. The new audio disc was enthusiastically received, especially in the early-adopting classical music and audiophile communities, and its handling quality received particular praise. As the price of players gradually came down, and with the introduction of the portable Walkman the CD began to gain popularity in the larger popular and rock music markets. The first artist to sell a million copies on CD was Dire Straits, with their 1985 album Brothers in Arms. The first major artist to have his entire catalogue converted to CD was David Bowie, whose 15 studio albums were made available by RCA Records in February 1985, along with four greatest hits albums. In 1988, 400 million CDs were manufactured by 50 pressing plants around the world.
answer:

CD players