How did new technologies make the building of skyscrapers practical

As I recall it was rolled-steel girders riveted together, probably from shipbuilding, together with steam-powered winches and an abundance of cheap steel. As opposed to European cathedrals erected with animal-powered winches and with more expensive forged iron bracing (one of the big cathedrals has a kind or iron corset to keep the walls from bursting outwards).

the statement the greek philosophers aristotle and plato would be most likely to agree with is statement c, a countries leader should be motivated by the common good of the country.

probably that america is racist