S-waves can only travel through Solids. They can not travel through a Liquid or a Gas.
The correct answer to this open question is the following.
Existentialism, anti-colonialism, and the quest for personal freedom influenced the landmarks of the last fifty years in that they were the dominant concepts that supported Neoliberalism, as the imperative economic system in modern western societies.
During these last fifty years, those concepts shaped the thinking of corporate America. An economic and political system that promoted free market, where corporations became so rich, countries signed free trade agreements, multinational companies opened branches in many third world companies, and unfortunately, it never impacted in a positive way to the working class, just benefited the rich people.
That is why today we see so many protests and demonstration in many countries, including the US, where people are demanding drastic changes after the US Crisis of 2008, when the federal government decided to support and rescue the big bankers and corporations, instead of supporting the interests of the common American citizen.
Tech tools , outsourcing morale , attitude , & the boss.
The Transcontinental Railroad innovation had the GREATEST impact on westward migration immediately after the American Civil War.
After the Civil War, there was great interest and opportunity with westward expansion. With the invention of the railroad, the transport of goods and people became quicker and less expensive than ever before.
