Q13. The 'pounding feet of the tourists' strongly juxtaposes the 'city's fragile stones', characterising the damage caused by tourists in comparison to the frailer nature of the ancient city of Machu Picchu.
Q14. The author is communicating that an organisation, WMF is trying to develop more policies and campaigns to allow tourists to practice sustainable tourism, with the preservation of sites under threat like Machu Picchu in mind.
A) Nor is a conjunction
B) Neither is a conjunction. Look up the acronym FANBOYS IT SHOWS A LIST OF CONJUCTIONS
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The answer to your question is "long term."
Hope this helped.