In this task, you are given a question and a context passage. You have to answer the question based on the given passage.
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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: Universal's parent company purchased Universal from whom?, Context: Matsushita provided a cash infusion, but the clash of cultures was too great to overcome, and five years later Matsushita sold an 80% stake in MCA/Universal to Canadian drinks distributor Seagram for $5.7 billion. Seagram sold off its stake in DuPont to fund this expansion into the entertainment industry. Hoping to build an entertainment empire around Universal, Seagram bought PolyGram in 1999 and other entertainment properties, but the fluctuating profits characteristic of Hollywood were no substitute for the reliable income stream gained from the previously held shares in DuPont.

Answer: Matsushita


Question: Who is Pytheas?, Context: Notable Greek seafarers include people such as Pytheas of Marseilles, Scylax of Caryanda who sailed to Iberia and beyond, Nearchus, the 6th century merchant and later monk Cosmas Indicopleustes (Cosmas who sailed to India) and the explorer of the Northwestern passage Juan de Fuca. In later times, the Romioi plied the sea-lanes of the Mediterranean and controlled trade until an embargo imposed by the Roman Emperor on trade with the Caliphate opened the door for the later Italian pre-eminence in trade.

Answer:
Greek seafarers