The underlined portion of the sentence provided is a nonessential adjective clause, characterized by the use of "which" and the use of commas.
<h3>What is an adjective clause?</h3>
As the name suggests, an adjective clause is a clause that functions as an adjective inside the sentence. It contains a subject and a predicate, and it starts with a relative pronoun.
Examples of relative pronouns are the following:
An adjective clause can be restrictive or nonrestrictive, also called essential or nonessential. When it is nonessential, it appears between commas. Being nonessential means it can be removed from the sentence, and the meaning of that sentence will not be altered.
That is the case with the clause "which was used by early man to make arrowheads." It starts with the relative pronoun "which," is set off by commas, and can be removed from the sentence.
Therefore it is a nonessential adjective clause.
Note: The complete question is the following:
Classify the underlined part of the following sentence by the type of phrase or clause it is.
Obsidian, which was used by early man to make arrowheads, is a naturally occurring glass.
A. Essential adverb clause
B. Nonessential adjective clause
C. Nonessential adverb phrase
D. Essential adjective phrase.
Learn more about adjective clauses here:brainly.com/question/1047465
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