Final answer:
The group of words 'where they live in underground burrows' is a clause that functions as an adverbial clause.
Step-by-step explanation:
The group of words in bold, 'where they live in underground burrows,' is a clause. A clause is a group of words that contains a subject and a verb and can express a complete thought. In this case, the clause 'where they live in underground burrows' is functioning as an adverbial clause, providing information about the location of the prairie crayfish.