What part of speech are the words am is and are?

The words "am," "is," and "are" are verbs. More specifically, they are forms of the verb "to be", which is considered a linking verb.

Here's why:

* Verbs: They express action, state of being, or occurrence.

* Forms of "to be": These words are used to connect the subject of a sentence to a predicate nominative (a noun or pronoun that renames the subject) or a predicate adjective (an adjective that describes the subject).

* Linking Verb: They link the subject to something that describes or identifies it.

Examples:

* I am happy. ("am" links "I" to the adjective "happy")

* She is a doctor. ("is" links "She" to the noun "doctor")

* They are students. ("are" links "They" to the noun "students")