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 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.
answer:
global temperatures


question:
Did more United States or Polish troops enter Iraq?, Context: After the lengthy Iraq disarmament crisis culminated with an American demand that Iraqi President Saddam Hussein leave Iraq, which was refused, a coalition led by the United States and the United Kingdom fought the Iraqi army in the 2003 invasion of Iraq. Approximately 250,000 United States troops, with support from 45,000 British, 2,000 Australian and 200 Polish combat forces, entered Iraq primarily through their staging area in Kuwait. (Turkey had refused to permit its territory to be used for an invasion from the north.) Coalition forces also supported Iraqi Kurdish militia, estimated to number upwards of 50,000. After approximately three weeks of fighting, Hussein and the Ba'ath Party were forcibly removed, followed by 9 years of military presence by the United States and the coalition fighting alongside the newly elected Iraqi government against various insurgent groups.
answer:
United States


question:
Who tried to portray their opponent as someone who had alienated American allies by his foreign policy?, Context: Bush focused his campaign on national security, presenting himself as a decisive leader and contrasted Kerry as a "flip-flopper." This strategy was designed to convey to American voters the idea that Bush could be trusted to be tough on terrorism while Kerry would be "uncertain in the face of danger." Bush (just as his father did with Dukakis in the 1988 election) also sought to portray Kerry as a "Massachusetts liberal" who was out of touch with mainstream Americans. One of Kerry's slogans was "Stronger at home, respected in the world." This advanced the suggestion that Kerry would pay more attention to domestic concerns; it also encapsulated Kerry's contention that Bush had alienated American allies by his foreign policy.
answer:

Kerry