The essential appositive in the sentence "astronomer maia mitchell discovered a comet in 1847 and went on to become the first professional female astronomer in the united states," is Maia Mitchel. The last option is correct.
An appositive consists on a noun or noun phrase that renames another noun right beside it. The appositive can be a short or long combination of words.
In this particular case, the words Maia Mitchell which is a proper noun is renaming the noun astronomer, which is right before it and constitutes the subject of the sentence.
An appositive is illustrated as the noun words or phrase that defines another noun it follows. It functions to rename or explain the noun or pronoun by proposing additional information about it.
In the given statement, the essential appositive would be 'Maria Mitchell' as it renames the noun 'astronomer' right beside it by adding further information about the astronomer. Thus, <u>option D</u> is the correct answer as the other options do not define or elaborate a noun.
