Answer:
While a dictionary is not supplied in this question, <em>harrow</em> means to cause distress. hope this helps :)
I think URL, because its <span> the generic term for all types of names and addresses that refer to objects on the World Wide Web. if im wrong im sorry :/</span>
Switching from chains to cables in the building of roller coasters was important because cables are less likely to snap when hauling several tons of roller coaster cars full of people. Chains are made of linked, welded pieces of metal that can easily snap if they pull too much. Cables, while they can snap, are much less likely to do so, because they're a stretch of fibers, be it metal or other, without any potential weak spots.