The two most important new technologies that enabled the development of the skyscraper were

Answer

The Elevator and mass-produced steel

Explanation

The mass production of steel enabled the development of skycrapers because steel facilitated the design of reinforced concrete structures that a new technology in building sector.Different designs of elevators facilitated the movement of building materials over the heights and ensured safety of workers too.

a. because the u.s. was the leading with the most technology, economy, etc. also was teamed with other allies witch boosted the economy and materials to improve technology and use it.

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