Final answer:
An introductory phrase provides context to the main sentence.
Explanation:
The canyon, formed by years of erosion, is an introductory phrase in the sentence.
Introductory phrases provide additional information about the main part of the sentence but are not essential to its basic meaning. In this case, the phrase 'formed by years of erosion' gives context to the canyon's origin.
Identifying and understanding introductory phrases can assist in comprehending the structure and flow of sentences.
Learn more about Introductory Phrases here:
https://brainly.com/question/33448108
