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

Example input: what is the first event mentioned?, Context: The Russian Revolution is the series of revolutions in Russia in 1917, which destroyed the Tsarist autocracy and led to the creation of the Soviet Union. Following the abdication of Nicholas II of Russia, the Russian Provisional Government was established. In October 1917, a red faction revolution occurred in which the Red Guard, armed groups of workers and deserting soldiers directed by the Bolshevik Party, seized control of Saint Petersburg (then known as Petrograd) and began an immediate armed takeover of cities and villages throughout the former Russian Empire.
Example output: Russian Revolution
Example explanation: This is a good example, and the Russian Revolution is the first event mentioned.
Q: How was access gained to Alaska, Context: The specifics of Paleo-Indian migration to and throughout the Americas, including the exact dates and routes traveled, provide the subject of ongoing research and discussion. According to archaeological and genetic evidence, North and South America were the last continents in the world with human habitation. During the Wisconsin glaciation, 50–17,000 years ago, falling sea levels allowed people to move across the land bridge of Beringia that joined Siberia to north west North America (Alaska). Alaska was a glacial refugia because it had low snowfall, allowing a small population to exist. The Laurentide Ice Sheet covered most of North America, blocking nomadic inhabitants and confining them to Alaska (East Beringia) for thousands of years.
A:
the land bridge