Final answer:
The underlined group of words 'which combines realism with abstraction' is a relative clause that provides additional information about something mentioned previously.
Step-by-step explanation:
The underlined group of words, which combines realism with abstraction, is a relative clause.
A relative clause is a dependent clause that starts with a relative pronoun (such as 'which', 'who', 'whom', 'whose', or 'that') and functions to provide more information about a noun or pronoun in the main clause. In this case, the relative clause 'which combines realism with abstraction' is providing additional information about something that has been mentioned previously.
For example, in the sentence 'I love art, which combines realism with abstraction,' the relative clause is describing the type of art that the speaker loves.