In the sentence, 'Sixty-five percent of the tulips in this field are white', what is the reason for the subject-verb agreement?

The sentence "Sixty-five percent of the tulips in this field are white" demonstrates proper subject-verb agreement because the verb "are" correctly agrees with the plural noun "tulips." In this construction, the phrase "Sixty-five percent of the tulips" identifies "tulips" as the subject of the verb; therefore, the plural form "are" is appropriate since it aligns with the plural subject "tulips."

The phrase "Sixty-five percent" serves as a descriptor indicating the quantity of the tulips, but it does not influence the form of the verb. Instead, it is the noun following the preposition "of" that determines the agreement. As such, using "are" matches the plural subject and maintains grammatical correctness in the sentence.