The sentence that has an adverb clause is:
Although we might consider animals as pets, many animals work.
The adverb clause is ALTHOUGH WE MIGHT CONSIDER ANIMALS AS PETS.
Adverb clause are identified as such when it complete these requirements.
1) has subject and verb. We + consider
2) has subordinate conjunction. Although
3) answers one of the four adverb questions (how, when, where, or why)