In this task, you are given a question and a context passage. You have to answer the question based on the given passage.

What would an engine driver have to do to adjust the more modern type of valve?, Context: Steam engines frequently possess two independent mechanisms for ensuring that the pressure in the boiler does not go too high; one may be adjusted by the user, the second is typically designed as an ultimate fail-safe. Such safety valves traditionally used a simple lever to restrain a plug valve in the top of a boiler. One end of the lever carried a weight or spring that restrained the valve against steam pressure. Early valves could be adjusted by engine drivers, leading to many accidents when a driver fastened the valve down to allow greater steam pressure and more power from the engine. The more recent type of safety valve uses an adjustable spring-loaded valve, which is locked such that operators may not tamper with its adjustment unless a seal illegally is broken. This arrangement is considerably safer.[citation needed]
seal illegally is broken

What gave these hunters their food supply?, Context: Evidence suggests big-game hunter gatherers crossed the Bering Strait from Asia (Eurasia) into North America over a land bridge (Beringia), that existed between 47,000–14,000 years ago. Around 18,500-15,500 years ago, these hunter-gatherers are believed to have followed herds of now-extinct Pleistocene megafauna along ice-free corridors that stretched between the Laurentide and Cordilleran ice sheets. Another route proposed is that, either on foot or using primitive boats, they migrated down the Pacific coast to South America.
big-game

Which country was demonstrating the protests?, Context: Argentine activists told a news conference that they would not try to snuff out the torch's flame as demonstrators had in Paris and London. "I want to announce that we will not put out the Olympic torch," said pro-Tibet activist Jorge Carcavallo. "We'll be carrying out surprise actions throughout the city of Buenos Aires, but all of these will be peaceful." Among other activities, protesters organized an alternative march that went from the Obelisk to the city hall, featuring their own "Human Rights Torch." A giant banner reading "Free Tibet" was also displayed on the torch route. According to a representative from the NGO 'Human Rights Torch Relay', their objective was to "show the contradiction between the Olympic Games and the presence of widespread human rights violations in China"

Argentine