Answer:
It contains a subject and a verb.
It is not set apart by punctuation.
It is essential to the meaning of the sentence.
Explanation:
A restrictive clause provides further meaning to the noun in a sentence. It contains a subject and a verb and is not separated from the sentence by punctuation marks.
An example is; The boy who I love to help is there. In this sentence, the restrictive clause is, "who I love to help". 'I' is the subject while 'help' is the verb.
