The sentence in which the underlined phrase is an adverb clause is the following one: Although we might consider animals as pets, many animals work.
Explanation:
Adverb clauses, also known as adverbial clauses, are dependent clauses that function as adverbs. Since they are dependent clauses, they must have a subordinating conjunction to link them to the rest of the sentence. In the sentence above, the adverb clause is "although we might consider animals as pets". It is an adverb clause of concession introduced by the subordinating conjunction <em>although. </em>
