Skyscrapers is a noun. It's the plural form of skyscraper.
No, the noun 'skyscraper' is not a standard collective noun. However, collective nouns are an informal part of language, any noun that suits the context of the situation can function as a collective noun; for example, a skyscraper of bureaucrats, a skyscraper of commerce, a skyscraper of excess, etc.
The average height of a story in a skyscraper is 8 to 10 feet, depending on what part of the world it is built in. The average total height of a skyscraper will also vary depending on what region it is in.
part of speech
The part of speech for this particular word is a noun.
adverb
what part of speech is beneath
The part of speech for "answer" is a noun.
The part of speech for "explicit" is an adjective.
The part of speech for "unfamiliar" is an adjective.
The part of speech for "indefinite" is an adjective.
The part of speech for "lecturer" is a noun.