The Alps are mountains that serve as a physical boundary between countries in Europe. According the article, the Swiss have created the world’s longest tunnel. How will this new tunnel revolutionize transportation in Europe and overcome this physical barrier? (Site 1)

Transportation has become much faster, cheaper, and safer through the tunnel built by the Swiss.

Explanation:

The Alps are a natural barrier that separtes the Apennine Peninsula from the  Balkan Peninsula, Central Europe, and Western Europe. Even though these are the highest and most massive mountains in Europe, the transportation infrastructure has been of very high quality, mainly because all countries that have a share of the Alps are well-developed ones. Despite this, transportation has been slow, expensive, and risky through the Alps.

This all has changed with the construction of the longest tunnel in the world built by the Swiss. This tunnel has cut the distance significantly between the countries. Transportation has become much faster and with it much cheaper, so it has been of great economical importance. Last but not least, all of the dangers that the Alps bring to transportation on the surface infrastructure are not present in the tunnel, so safety is not an issue.

answer; i believe that the correct answer is (the explosion of a nearby star(supernova);