Answer:
Rascacielo
Step-by-step explanation:
Let’s translate the sentence first:
Un_______ es un edificio muy alto.
translates to:
A _______ is a very tall building.
Buildings that are very tall are also called skyscraper.
The word for skyscraper in Spanish is: rascacielo
Therefore, the answer is: rascacielo.
The completed sentence is: Un rascacielo es un edificio muy alto.