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

[EX Q]: What did the land bridge between the Americas cause to change?, Context: South America became linked to North America through the Isthmus of Panama during the Pliocene, bringing a nearly complete end to South America's distinctive marsupial faunas. The formation of the Isthmus had major consequences on global temperatures, since warm equatorial ocean currents were cut off and an Atlantic cooling cycle began, with cold Arctic and Antarctic waters dropping temperatures in the now-isolated Atlantic Ocean. Africa's collision with Europe formed the Mediterranean Sea, cutting off the remnants of the Tethys Ocean. Sea level changes exposed the land-bridge between Alaska and Asia. Near the end of the Pliocene, about 2.58 million years ago (the start of the Quaternary Period), the current ice age began. The polar regions have since undergone repeated cycles of glaciation and thaw, repeating every 40,000–100,000 years.
[EX A]: global temperatures

[EX Q]: Why were 78s more popular than 45s in 1954-55?, Context: Some of Elvis Presley's early singles on Sun Records might have sold more copies on 78 than on 45. This is because the majority of those sales in 1954–55 were to the "hillbilly" market in the South and Southwestern United States, where replacing the family 78 rpm player with a new 45 rpm player was a luxury few could afford at the time. By the end of 1957, RCA Victor announced that 78s accounted for less than 10% of Presley's singles sales, essentially announcing the death throes of the 78 rpm format. The last Presley single released on 78 in the United States was RCA Victor 20-7410, I Got Stung/One Night (1958), while the last 78 in the UK was RCA 1194, A Mess Of Blues/Girl Of My Best Friend (1960).
[EX A]: replacing the family 78 rpm player with a new 45 rpm player was a luxury few could afford

[EX Q]: Who is responsible for running the elevator?, Context: A climbing elevator is a self-ascending elevator with its own propulsion. The propulsion can be done by an electric or a combustion engine. Climbing elevators are used in guyed masts or towers, in order to make easy access to parts of these constructions, such as flight safety lamps for maintenance. An example would be the Moonlight towers in Austin, Texas, where the elevator holds only one person and equipment for maintenance. The Glasgow Tower — an observation tower in Glasgow, Scotland — also makes use of two climbing elevators.
[EX A]:
its own propulsion

